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Our take —

In contrast to a recent report of high attack rates of SARS-CoV-2 among children and staff in a Georgia overnight summer camp, this report of over one thousand attendees of four Maine overnight camps did not identify any secondary transmissions after three asymptomatic attendees (among over one thousand) showed evidence of infection by PCR during camp. Protocols included mandatory PCR testing for all attendees in the week prior to the beginning of camp, daily symptom screening, one follow-up PCR test roughly a week after the beginning of camp, isolation of suspected cases, quarantine of exposed cohorts, and multiple other non-pharmaceutical interventions during camp activities. The report suggests that strong testing and isolation protocols can prevent significant secondary transmission of SARS-CoV-2, even in a congregate setting with multiple close contacts, when there are a small number of initial cases.

Study design

Other

Study population and setting

This report describes non-pharmaceutical interventions to limit spread of SARS-CoV-2 among 1,022 campers and staffers (63% campers, 37% staff members; 54% female) in four overnight summer camps in the U.S. state of Maine from June 15 to August 18, 2020. Attendees and staff ranged in age from 7 to 70 years old, and were from 41 U.S. states (98%) and 6 international locations (2%). The numbers of attendees in the four camps ranged from 202 to 287, and the duration of each camp ranged from 44 to 62 days. PCR testing for SARS-CoV-2 infection was required prior to camp arrival for attendees (testing ranged from 2-9 days before the start of camp). Upon arrival, all attendees were quarantined by cohort (ranging in size from 5-44 campers) for 14 days after arrival. Attendees were screened at least once daily for fever (with an infrared thermometer) and other symptoms (verbally). Attendees were tested again with PCR (4-9 days after arrival, with results available 2-3 days later). Those with symptoms or with a positive test result were isolated, and their cohort was quarantined, until a negative test result was obtained. Attendees were instructed on hygiene and were required to wash hands with soap and water or use hand sanitizer (minimum 60% ethanol or 70% isopropanol) after all activities with a high degree of touching, including meals. Other modifications to camp protocols included requiring mask use and 6-foot physical distancing for any mixed-cohort interaction, limiting indoor mixed-cohort events, restricting sports to those permitting physical distancing, providing cohort-specific bathrooms (or staggering use by cohort), and enhanced cleaning and sanitizing. Protocols were enforced by camp staff members, and no staff member left the camp during time off.

Summary of Main Findings

Of the 1,022 attendees, 12 had received a prior diagnosis of COVID-19 and had completed their isolation over two months before camp began; they were not subsequently tested. Of the 1,010 attendees initially tested via PCR for SARS-CoV2 infection, four (0.4%) asymptomatic individuals tested positive, completed 10 days of isolation at home, did not develop symptoms, and were allowed to attend camp with no further testing. The remaining 1,006 attendees were subject to one repeat PCR test while attending camp. Three (0.3%) asymptomatic attendees (two staff members and one camper) tested positive. The two staff members were isolated for 10 days and received two consecutive negative results at the end of their isolation. Their cohorts (n=5, n=6) were quarantined for 14 days. The infected camper was isolated for 8 days and released after a second negative test result; the 30 cohort members of the camper were tested 3-4 days after the initial positive result. Quarantine for the camper’s cohort ended when the camper was released from isolation. There were no secondary infections identified. Screening identified 12 individuals with symptoms consistent with COVID-19; these individuals were isolated and tested and their cohorts were quarantined. All 12 received subsequent negative test results.

Study Strengths

Protocols were fairly well described. The study population was large, represented a wide range of ages, and came from diverse regions within the United States.

Limitations

There was no measurement of adherence to NPIs. The report does not state whether the cohorts of the two infected staff members were subsequently tested. Attendees were not tested at the end of camp, so some secondary transmission may have been missed. Since all cases were asymptomatic and positivity rates were so low, it is conceivable that cases were false positives, and that no attendees were infectious upon arrival at camp. If so, no conclusions could be drawn about the effectiveness of the NPIs during camp.

Value added

This report highlights the potential benefit of rigorous testing and isolation protocols in minimizing secondary transmission of SARS-CoV-2, despite repeated long-duration contact in an overnight setting.

Our take —

This study reported on results of a new protocol for channeling incoming prisoners through a standardized protocol of testing and quarantine. In contrast to the mass outbreaks seen in many other U.S. correctional facilities, only two cases were observed after initiation of the new protocol. Rigorous testing and isolating of incoming prisoners, limiting sharing of common facilities in prisons, and isolation of anyone who develops symptoms, is an effective way to reduce SARS-CoV-2 transmission in a high-risk congregate setting.

Study design

Other

Study population and setting

In mid-March 2020, the Puerto Rico Department of Health implemented a protocol to prevent and manage COVID-19 in all publicly-run prisons in Puerto Rico based on interim guidance from the CDC. This study reports on test results among all 1,340 newly incarcerated people in Puerto Rico from March 16 to July 31, 2020, after implementation of the new protocol. The new protocol focused on: (i) revised intake procedures for newly incarcerated persons and returning prisoners; (ii) limited sharing of common areas in facilities; and (iii) isolation of any symptomatic persons. Newly incarcerated persons were all processed at one location, and everyone, regardless of symptoms, was tested using RT-PCR. People were then separated into groups of no more than 20. If everyone in the group tested negative, and no one developed symptoms during 14 days of quarantine, then the group was permitted to enter the general prison population. Anyone testing positive or with other health issues/symptoms was isolated and taken to the prison medical facility, prompting a reset of the entire process. Any incarcerated person leaving the prison was required to undergo the intake process upon return. The general prison population was separated into groups of 40-75 people with each group having their own common areas. Any individual that developed symptoms was promptly isolated and the rest of the group quarantined. In May, all willing incarcerated persons were tested using a point-of-care antibody test to test for previous and recent/active infection.

Summary of Main Findings

The revised protocol appears to have been successful at preventing transmission in incarcerated populations. Between March and July, 2020 1,340 newly incarcerated persons went through the revised intake protocol, with two people testing positive during the initial intake process. Based on the serologic testing in May, 0.3% (31 out of 8,619) tested positive for IgG antibodies to SARS-CoV-2 (indicating past infection); no one tested positive for IgM antibodies (indicating a recent/active infection).

Study Strengths

The study provides a comprehensive description of protocols used to limit the spread of COVID-19 amongst a network of prisons. Mass serologic testing provided an estimate of prevalence of recent and past infection.

Limitations

Despite serologic testing being offered to every incarcerated adult, no detail was provided on the number who opted out of testing, making it difficult to assess how effective the protocol was. The sensitivity and specificity of the antibody test was not reported; the specificity is of particular interest in this setting of apparently low prevalence. For implementation purposes, details of additional resource requirements (e.g. staffing, financing) would have been useful. No data were provided on incidence or prevalence of SARS-CoV-2 infection in either the general population of Puerto Rico or in a subpopulation with similar demographic characteristics as the newly incarcerated inmates. Elements of the protocol may not be applicable to settings with higher population density, where cohorting into small groups is impractical.

Value added

The authors describe, in detail, practical ways to reduce SARS-CoV-2 transmission in prison facilities in Puerto Rico.

Our take —

This study sought to examine workplace-associated COVID-19 outbreaks in Utah comparing across industry sectors. The most represented industries were manufacturing, construction, and wholesale trade. Hispanic and Black, Indigenous, and other people of color were at increased risk of infection compared to the overall population likely due to overrepresentation in these industries. The study likely did not include smaller workplaces in its analysis, and could not account for workplace changes due to stay-at-home orders or restrictions, thus likely underestimating attack rates amongst those who were at shared work locations.

Study design

Ecological, Other

Study population and setting

The study objective was to report the number of COVID-19 cases traced to workplace settings in Utah as determined by the state’s COVID-19 surveillance system. From March 6 to June 5, 2020, 277 COVID-19 outbreaks were reported, representing 1,389 COVID-19 cases out of 11,448 across the state (12%). Workplace outbreaks were defined as having two or more laboratory-confirmed cases within the same 14-day window among coworkers at the same facility. Utah Department of Health (UDOH) investigators collected the addresses and/or business names for all outbreaks and classified them into 20 industry sectors as determined by the North American Industry Classification System (NAICS), as obtained by the Division of Corporations and Commercial Code business registry the Utah state government maintains. Cases per 100,000 workers were calculated using estimates from the 2019 Census Quarterly Workforce Indicators. Race/ethnicity information, hospitalization status, and number of severe outcomes were also collected.

Summary of Main Findings

Of the 277 outbreaks in the state, 210 were linked to workplaces (75.8%), representing 1,389 cases. The most represented industries were manufacturing (20%), construction (15%) and wholesale trade (14%), which made up the majority of cases (806 total cases in these three sectors). The workplace outbreak attack rate was 106.4 cases per 100,000 workers overall, and was highest among manufacturing (339.4 per 100,000 workers) and wholesale trade (377.0 cases per 100,000 workers). Of the 1335 cases with race/ethnic data available, 73% were among Hispanic or Black, Indigenous and people of color (N=970). 85 were admitted to the hospital (6%) and 40 had severe outcomes (3%). The median cases per outbreak was 4, with ranges from 2 to 79 cases. Compared with people in the state 15 years or older, people with workplace-associated COVID-19 tended to be older (41 years on average, compared to 38 years), more likely to identify as Hispanic (56.4% vs. 39.8%), and be male (61.4% vs. 50.6%).

Study Strengths

The study used the Utah surveillance system to identify all workplace outbreaks, and were able to report on a number of important sociodemographic disparities with their individual-level information. Additionally, using the population of working age in the state, they were able to examine whether those with workplace-related COVID-19 were getting sick at a higher rate or not, which has important insights for the type of workers being placed most at risk. Additionally, they used lab-confirmed diagnosis of COVID-19, which reduced misclassification in their results (though they do not state what type of lab test was used).

Limitations

Grouping by industries shows important trends, but further disaggregation for the main categories (e.g., what type of wholesale trade or manufacturing) would given further insight into what conditions may be leading to the increased risk of outbreaks. Additionally, they do not collect temporal trends that may have altered the probability of an outbreak, such as mandatory closures, and may have affected certain industries more than others. If a handful of industries remained closed throughout the study period, then they would have fewer outbreaks regardless of the actual working conditions, and would not be a valid comparison to industries who did not face these closures. Additionally, worker-to-worker transmission could not be confirmed, and outbreaks that had two individuals who were independently infected would still be included in the analysis. Outbreaks in smaller workplaces would also likely be left out of this analysis.

Value added

This is one of the largest by-sector workplace analyses in the US that also collected race/ethnicity and age data to further identify populations most at risk for infection.

Our take —

This study finds that people in Germany are more likely to wear masks given a mandatory mask policy rather than a voluntary one, and that such a mandatory policy would be viewed as more fair.

Study design

Other

Study population and setting

Between April 14 and May 26, 2020, the authors conducted approximately 6,973 online surveys (~1,000 per week) in Germany to assess changes in mask-wearing knowledge, behavior, and attitudes. On April 27, 2020, masks were required on public transport and in shops. Participants were recruited based on age and gender, and by state in Germany. In addition, during the May 26/27 survey (n=925), a vignette was presented where respondents were asked to imagine that mask policies were mandatory (or not) and their reaction to another person who is wearing a mask (or not) in a grocery store. Subsequent questions assessed how the respondent felt about the person wearing a mask or not, perceived “fairness” of mandatory mask policies, stigma associated with mask-wearing, and if the other person was perceived as prosocial (i.e. helpful, positive, concern for the welfare and rights of others).

Summary of Main Findings

The proportion of respondents reporting either often or always wearing masks increased dramatically April 14 and May 26. Those reporting wearing masks were more likely to also report other protective behaviors (avoiding handshakes, washing hands, and keeping physically distant) compared to those that did not wear a mask. The support for mandatory mask measures was stable over time at just under 60%. Respondents with more prosocial concerns (concerned about the welfare and rights of others), were more likely to report wearing masks. However, prosocial concerns were not associated with intent to wear a mask in the future. Mask wearers are likely to view other mask wearers more favorably regardless of whether mask-wearing is mandated or voluntary. Based on results from the vignette, when comparing voluntary versus mandated mask-wearing measures, voluntary policies suggested that less people would wear masks (77% versus 96%); respondents were more likely to judge other mask-wearers as being part of a group with higher risk of complications from COVID-19 (i.e. those over 50 years and/or those with pre-existing medical conditions) but not significantly more likely to have COVID-19; and voluntary policies were perceived as less “fair” especially among respondents that reported being part of a risk group.

Study Strengths

The study surveyed a large group (n=6,973) of participants weekly and stratified based on age and sex, and state in Germany. Their survey also used a variety of measures to assess attitudes towards masks allowing for more nuanced interpretation.

Limitations

It is unclear how or whether the results from Germany would apply to other contexts. Values and attitudes to mask-wearing policies will be influenced by country-specific cultures and broader perceptions of COVID-19. Views on mandatory versus voluntary mask-wearing policies and stigma associated with mask-wearing were based on a single and highly specific vignette, and it is unclear if results would vary if different vignettes were presented. Analysis of survey results also separated respondents into two groups: those that perceptive COVID-19 measures were exaggerated, and those that did not. Group membership was determined based on the median response at each survey time-point. Finally, data presented here is based on self-report rather than actual behaviors. As a result, respondents may be more likely to report behaviors that they believe are more socially desirable.

Value added

Based on the results presented, mask-wearing increased over time and was associated with other protective behaviors. Furthemore, mandatory mask policies are more likely to result in more people wearing masks, less likely to result in mask-associated stigma, and are more likely to be perceived as “fair” in Germany. It is unclear if these results can be applied to countries other than Germany.

Our take —

In this study of healthcare workers providing SARS-CoV-2 counseling to thousands of asymptomatic family contacts of infected cases in India, 12/62 tested positive before the introduction of plastic face shields, but 0/50 tested positive after face shields were introduced.  Masks, gloves, and hand sanitizer were used throughout both periods.  Although it is possible that workers practiced more caution during the post-shield period in a way that was unmeasured, the results strongly suggest that face shields reduced transmission of SARS-CoV-2 from asymptomatic contacts to healthcare workers.

Study design

Other

Study population and setting

This study followed community health care workers who counseled asymptomatic family contacts of index SARS-CoV-2 cases in Chennai, India.  Rates of laboratory-confirmed SARS-CoV-2 infection among health care workers were compared between two periods: from May 3 to May 15, 2020, before the introduction of 250-micrometer polyethylene terephthalate (PET) face shields (n=62); and from May 20 to June 30, 2020, after face shield introduction (n=50).  Workers lived in separate rooms of a hostel and had no physical contact with one another after the training period; they did not visit their homes or public places during the study period. Workers traveled between households in vans with partitions separating them from drivers. Throughout the study period, workers also used surgical masks, gloves, shoe coverings, and alcohol-based hand sanitizers.  During household visits, masked workers provided SARS-CoV-2 counseling in the front room of households, standing at least 6 feet away from assembled family members. Family members were advised to wear masks, although some did not wear them.  On May 20, 2020, face shields were added to protocols; shields were treated with alcohol sanitizer after each visit and soaked in a water-detergent solution nightly.

Summary of Main Findings

In the pre-shield period, 62 workers visited 5,880 households with 31,164 people; 222 people in these households later tested positive for SARS-CoV-2.  Two workers developed symptoms (symptoms appeared in the first worker 13 days after household visits began) and subsequently tested positive for SARS-CoV-2, resulting in testing of all other workers from May 16-19.  A total of 12 (19%) tested positive: 8 were symptomatic and 4 were asymptomatic.  After face shields were implemented, 50 previously uninfected workers visited 18,228 households with 118,428 people; 2,682 later tested positive for SARS-CoV-2.  All workers were screened for symptoms and tested via RT-PCR for SARS-CoV2 weekly during this period.  None of the 50 workers tested positive for SARS-CoV-2 infection from May 20 to June 30, 2020.

Study Strengths

Workers had few sources of exposure to SARS-CoV-2 other than household visits to asymptomatic contacts of index cases.  The protocols designed to limit transmission during the two periods appeared to be identical other than the exposure of interest.  A large number of households were visited by workers, with many subsequent positive tests among household contacts, representing a considerable risk of SARS-CoV-2 transmission to workers during the face shield period.

Limitations

The before-after comparison makes it difficult to be certain that other conditions did not contribute to the reduction in transmission to health care workers.  For example, the positive test results in the pre-shield period may have encouraged behaviors and precautions among workers that were not measured. Testing procedures and indications were not well described, particularly during the post-shield period. This study assessed SARS-CoV-2 infection status using PCR (i.e., antigen testing) only; thus, some infected workers may have been missed if they were not tested while shedding detectable virus. Antibody testing would have improved interpretability of results.

Value added

This is the first study to date assessing the independent effectiveness of face shields in reducing the transmission of SARS-CoV-2.  

Our take —

This study conducted qualitative in-depth interviews with 30 informal settlement dwellers receiving food assistance in Tshwane, South Africa during a COVID-19 lockdown. Interviews revealed the deleterious economic, social, and health-related impacts of COVID-19 lockdown policies on low-income households and communities.

Study design

Cross-Sectional, Other

Study population and setting

The authors conducted telephone interviews with 30 men and women receiving pandemic relief assistance from humanitarian organizations operating in informal settlements in Tshwane, South Africa. Interviews were conducted during the 21-day lockdown imposed by South Africa’s government, which mandated the closure of all schools and non-essential business and required all South Africans to shelter in place if not reporting for an essential job, seeking medical care, or purchasing food or other essential items.

Summary of Main Findings

Participants reported difficulties adhering to social distancing recommendations, given overcrowded housing conditions in informal settlements. In spite of the lockdown orders, participants expressed concerns about COVID-19 transmission in informal settlements due to people continuing to congregate in public spaces. Increased strain on public infrastructure, including waste management, due to crowding within the settlement was an unintended consequence of the lockdown. Many participants were forced deeper into poverty due to lost wages from business closures. Insufficient money also exacerbated food insecurity, which some participants reported destabilized medication adherence for people living with HIV and tuberculosis. While South African schools adapted to online modalities of delivery, poor internet connectivity and lack of internet access in many households resulted in temporary school discontinuation and attrition. Lastly, increased isolation due to mobility restrictions increased sentiments of anxiety and depression.

Study Strengths

The authors implemented qualitative interviews to gain a deeper understanding of informal settlement dwellers’ experiences during the mandated national lockdown. The iterative thematic analysis of interview transcripts allowed the study team to interrogate and critically examine their interpretations of participant narratives captured in the interviews.

Limitations

Given the inductive and exploratory nature of the research, the authors could not probe or compare the experiences of informal settlement dwellers of Tshwane to those in other settings. Participants were also receiving pandemic relief from humanitarian organizations, which may render their experiences incomparable to those of other informal settlement dwellers or South Africans who did not receive or require this assistance. Additionally, the qualitative results summarized did not explicitly present comparisons in salient themes or experiences between participant strata, including gender or age.

Value added

This is among the first published studies to use qualitative methods to document the impact of COVID-related lockdowns on low-income individuals living in informal settlements, particularly in the African setting.

Our take —

Incidence of SARS-CoV-2 infection was high in Padua, Italy during the spring of 2020. This study documents universal screening and testing of newborns, parents, and staff at a neonatal ward in Padua during this period. Five parents and staff members tested positive and were immediately isolated for two weeks. Three newborns who had close contact with suspected or known cases were quarantined, but no neonates tested positive for SARS-CoV-2 infection. Universal screening and careful isolation of suspected cases may have helped prevent transmission to this highly vulnerable population of neonates.

Study design

Other

Study population and setting

This study describes outcomes of a screening and testing protocol in place at the neonatal ward of a single hospital in Padua, Italy from February 21 to April 21, 2020. All neonates (n=75) admitted during this period, along with their parents (n=114) and all staff (n=112) in the ward, were included in the study. At the start of the study period, the neonatal ward implemented a 5-part intervention aimed at controlling SARS-CoV-2 infection: 1) Parents were triaged for symptoms upon neonate admission and were asked about contacts with potential COVID-19 cases. Parents were allowed to visit neonates one at a time, for one hour per day only, and all parents were asked to wear gloves and masks while visiting; 2) All neonates, parents, and staff were tested with RT-PCR for SARS-CoV-2 infection via weekly nasopharyngeal (NP) swabs (high-risk patients were tested daily for the first 3 days after admission). All neonates were tested for IgG and IgM antibodies after April 7, 2020; 3) Individuals testing positive, and neonates born to mothers testing positive, were quarantined in a negative pressure room where parents were not allowed; 4) Neonates were kept separate from mothers with suspected or confirmed COVID-19, and all neonates with low birth weight or of low gestational age at birth were fed with donors’ milk; 5) Staff and parents were given guidance on reducing transmission. Personal protective equipment including eye protection, N95 respirators, gloves, and gowns were worn in quarantine areas.

Summary of Main Findings

No neonates tested positive for SARS-CoV-2 infection or for presence of SARS-CoV-2 antibodies during the study period. Of the 75 neonates, 36 (48%) required admission to intensive care, and 8 (11%) of these infants required mechanical ventilation. Three newborns (4%) were deemed high-risk and quarantined: one was born from a mother who required mechanical ventilation for severe SARS-CoV-2 respiratory distress, one was breastfed by a mother with asymptomatic SARS-CoV-2 infection, and one had close contact with an infected staff member. All three newborns repeatedly tested negative for SARS-CoV-2, and none subsequently seroconverted; they were moved out of quarantine after 14 days. The 112 staff members and 114 parents were subject to 6,726 triage procedures. Three parents had fever or flu-like symptoms and were not allowed entry, and each subsequently tested negative for SARS-CoV-2. A total of 954 nasopharyngeal swabs were collected from staff and parents. Two parents and three staff members (2.2%) tested positive for SARS-CoV-2; all were asymptomatic and isolated for 14 days, and none seroconverted. The authors reported qualitatively high compliance by parents and staff to all protocols.

Study Strengths

Most protocols and outcomes were well described. Antibody testing later during the study period provided a useful adjunct to RT-PCR.

Limitations

The interventions described here may not be generalizable to neonatal wards with different physical layouts (the pod-based arrangement of rooms allowed for a greater degree of physical separation than might be possible elsewhere). Universal testing may not be possible in resource-limited settings. Measures of adherence to protocols were not quantitatively assessed. Protocols for RT-PCR testing of neonates were not well described, and it is unclear how often this testing occurred. Cord blood, placenta, and amniotic fluid were not tested, so some SARS-CoV-2 infections among neonates may have been missed.

Value added

This study adds to a limited evidence base on universal screening and testing procedures among neonates, parents, and staff in neonatal wards.

Our take —

In the U.S. state of Maine, the overwhelming majority of COVID-19 contacts who participated in symptom monitoring opted to do so with an automated system using text messages or the web. Contacts who did not participate were not enumerated, making it difficult to draw broad conclusions about the effectiveness of this tool. Among all participating contacts, 12% developed COVID-19 (representing 10% of all cases in Maine during the study period), 68% of whom had household exposure; these findings are in line with estimates from contact tracing studies from South Korea and elsewhere.

Study design

Prospective Cohort, Other

Study population and setting

This study reported on 1,622 contacts (median age 29 years, 50% female) of 614 COVID-19 patients in the US state of Maine who were enrolled in an automated, web-based symptom monitoring program. Contacts were defined as anyone who was within 6 feet of an infectious contact (from 2 days before symptom onset to 10 days after symptom onset; for asymptomatic cases, the date of a positive test was used instead of symptom onset) for 15 minutes or longer. Contacts were instructed to report symptoms daily via an online questionnaire for the duration of their recommended 14-day quarantine; symptoms included cough, difficulty breathing, fever, chills, shaking with chills, muscle pain, headache, sore throat, and new loss of taste or smell. If contacts preferred not to report symptoms with the automated system, they were directly monitored by contact tracing investigators. Demographic information and symptom monitoring preferences were collected at enrollment. Case investigations were undertaken for any contact with a positive SARS-CoV-2 test result or with symptoms absent testing.

Summary of Main Findings

The vast majority (96%) of enrollees chose automated symptom monitoring over direct monitoring by public health investigators. Of those opting for automated monitoring, 60% preferred text message delivery, 21% preferred texted web link, 8% preferred telephone, and 8% preferred emailed web link. Twenty-nine percent of participants were enrolled within two days of their last contact with the index case. There were an average of 2.9 contacts per index case enrolled, and 29% of participating households had more than one enrollee. Among enrolled contacts with available data (76% for race, 63% for ethnicity), 59% were white and 39% were Black, while 4% identified as Latino or Hispanic. The primary language spoken by participants was reported as English by 80% of contacts, French by 7%, and Somali by 7%. Symptoms or a positive SARS-CoV-2 test result were reported by 231 (14%) enrollees, 190 (12%) of whom met the case definition for COVID-19. Of these 190, 127 had confirmed COVID-19, while the remaining 63 were considered probable cases. Probable and confirmed cases represented 10% of all reported cases (n=1869) in Maine during the study period. Of the 165 cases of COVID-19 among enrollees with data on source of exposure to the index case, 68% had household exposure, 18% had community exposure, and 16% had health care exposure. Four patients were hospitalized, and one died.

Study Strengths

Although the participation rate among all contacts is unknown, those who did participate provided useful data on preferences and outcomes. A sizable proportion of COVID-19 cases in Maine (10%) were identified through contact tracing and assessed via the automated monitoring program during the study period.

Limitations

Data were not available on the total number of contacts reported by index cases. Therefore, the participation rate could not be calculated, and it is not possible to draw strong conclusions about the acceptability of automated symptom monitoring. Additionally, if participation was low among contacts, the preferences, reporting behavior, and outcomes among this group of contacts may not be representative of contacts in Maine. Losses to follow-up may be under-reported, as they were not distinguished from those released from quarantine. Similarly, COVID-19 cases were likely under-reported, since SARS-CoV-2 testing was not required or administered to all contacts.

Value added

This study adds valuable (if incomplete) data on contact tracing preferences and outcomes, as few such results from the United States have been published to date.

Our take —

In a study of a single COVID-19 hospital room at the University of Florida, available as a preprint and thus not yet peer reviewed, viable virus was extracted from air samples. Though the concentration of viral particles per liter of air was low, viable virus was extracted between 2 and 4.8 meters away from where they patients were located. This study provides evidence of viable virus in the air, and further research is needed to understand the role of airborne transmission of SARS-CoV-2.

Study design

Other

Study population and setting

Air samples were collected from a single hospital room that housed two COVID-19 patients at the University of Florida Health Shands Hospital. One of the patients had active SARS-CoV-2 infection based on a positive nasopharyngeal test by RT-qPCR. Three, 3-hour air samples of airborne particles were performed serially using two air samplers. The air sampler uses a water-vapor condensation method in order to collect samples. Two samplers were used in order to collect samples from different parts of the room that were placed between 2 and 4.8 meters away from the patients. Material collected in the samples was subjected to RT-qPCR and viral culture; isolated virus extracted from the room and from a nasopharyngeal swab sample were subjected to genome sequencing for comparison.

Summary of Main Findings

Viable virus was isolated from air samples that were collected between 2 and 4.8 meters away (6.5 to 15.7 feet) from the patients. The genome sequence of the isolated virus collected from the air samplers matched that collected from the nasopharyngeal swab. Viral concentrations in the air were estimated to be between 6 and 74 TCID50 (mean tissue culture infectious dose) units/L of air.

Study Strengths

While previous studies were unable to isolate the virus, this study utilized a water-vapor condensation mechanism of air sampling, which increases the likelihood of isolating viable virus in tissue culture if virus exists. Further the data came from an area where the patient was known to have SARS-CoV-2 and the viral sequences between the patient and the recovered virus could be compared. Finally, different distances were used to collect the samples to test difference safe distances.

Limitations

This is a study of a single hospital room and the amount of viable virus isolated per liter of air was small. It is not possible to differentiate whether this small amount of virus was due to the characteristics of the hospital room, infectiousness of the individual infected with SARS-CoV-2, and/or methodological difficulties in actually extracting the virus. It is also not clear how characteristic of the patient affect the amount of detectable virus or the distance at which viral particles can be detected. As these patients were hospitalized, they may have been expressing more viable virus than a patient who was isolating at home.

Value added

This study provides evidence that viable SARS-CoV-2 may be found in aerosols, and suggests that further research should be conducted to better understand the role of airborne transmission. It may also point to need to increase recommended distancing protocols if the results are confirmed in other environments and patients.

Our take —

This study examined transmission within school and early childhood education centers before and following distance learning recommendations in New South Wales, Australia. Of 3033 COVID-19 cases in the region through May 1, 2020, 27 primary cases were identified in 25 educational settings, who had 1448 close contacts. Students and staff continued to attend while infectious for a median of 2 days, and there were 18 secondary cases identified overall across 4 settings. In these settings, staff-to-staff transmission had the highest rate (4.4% of contacts), followed by staff-to-child (1.5% of contacts), while child-to-child transmission had the lowest rate (0.3% of contacts). This study likely missed asymptomatic cases, and may underestimate the level of secondary transmission. However, it shows the low risk of transmission during school closures and other infection control policies throughout NSW.

Study design

Prospective Cohort, Other

Study population and setting

In New South Wales (NSW) Australia, the study identified children and school or early childhood education center (ECEC) staff from all confirmed COVID-19 cases in NSW. From January 25 to May 1, 2020, NSW had 3033 COVID-19 cases overall. Of these, 97 (3.2%) of the 3033 were children and 22 (0.7%) had links to an education setting (e.g. educators, ECEC staff). Because of school closures and other policies, 19 of these children attended an educational setting (school or ECEC) while infectious, and were included in the study sample. Among school staff, all 22 were identified as having attending school or ECEC during their infectious period and were also included in the study sample. Of these 41 cases identified, 27 were identified as primary cases in 15 schools and 10 ECEC settings, and using contact tracing, 1448 of their close contacts were identified, and 663 contacts were tested for COVID-19. The study was able to obtain symptom questionnaires from 288 contacts. During the study period, school attendance rates declined from 90% to 5% after distance learning recommendations were implemented March 23rd, 2020.

Summary of Main Findings

Of the 27 primary cases identified in the 25 educational settings, 15 were staff (55.6%) and 12 were children (44.4%). The median amount of time primary cases continued to attend school/ECEC was 2 days (range: 1 to 10 days). All of the primary cases had acquired the infection locally, with most exposure sources unknown, but, when known, mostly household contacts. There were 1448 close contacts monitored over the study period, and 663 (43.7%) were tested for COVID-19. Secondary transmission was identified among 4 settings (16.0%), with 3 schools and 1 ECEC, with 18 secondary cases (1.2% attack rate) identified through contact tracing in the schools/ECECs. Among 288 contacts with symptom questionnaire data, 22.6% (n=65) of them developed symptoms during the 14 day quarantine. Staff-to-staff transmission had the highest rate (4.4%), compared to staff-to-child transmission (1.5%) and child-to-staff transmission (1.0%), and child-to-child transmission (0.3%).

Study Strengths

The study identified all residents of NSW who tested positive, and determined their school attendance; while this did result in a small sample size, it reduced the potential selection bias for a representative sample of the area. They were also able to have a symptom questionnaire paired with contact tracing to understand how many people went on to develop symptoms, and how many continued to attend schools/ECECs. Using a prospective study, they also were able to temporally identify how changes in school policy (such as closures) reduced transmission in NSW.

Limitations

The study had small sample sizes, likely due to school closures which reduced transmission compared to what it would have been without these measures. Many contacts were tested after developing symptoms, so asymptomatic cases are likely still missing from this assessment. There was incomplete symptom data available for most close contacts as well, which may reduce the estimated number of secondary cases identified. Similarly, schools/ECECs defined close contacts and may have used differing definitions, which would also lead to contacts not being identified and reduced estimated case numbers. Finally, in their attack rate calculation, they limited it to individuals identified through their enhanced contact tracing, and did not include secondary cases identified through the NSW Department of Health population surveillance, which may deflate the estimated attack rate if these individuals were missed in the tracing

Value added

This is one of the largest studies that examines transmission in school and ECEC settings, including before and following school closures.