Lower SARS-CoV-2 household transmission in children and adolescents compared to adults

Secondary Attack of Symptomatic SARS-CoV-2 Infections Among Roommates in a Children's Hospital

BACKGROUND

SARS-CoV-2 can potentially cause nosocomial outbreaks. Although high secondary attack rates (SARs) among adult roommates have been reported, data on pediatric settings are limited. This study aimed to evaluate the SAR of symptomatic SARS-CoV-2 infections in shared rooms in a children's hospital.

METHODS

A retrospective chart review from January 1, 2023, to December 31, 2023, was conducted at the National Center for Child Health and Development, one of the largest tertiary children's hospitals in Japan. According to hospital policy, nucleic acid amplification tests for SARS-CoV-2 were required for all hospitalized patients who developed new-onset fever or respiratory symptoms during the study period. If the test result was positive, confirmed cases with SARS-CoV-2 infection were immediately transferred to an isolation ward, and their remaining roommates were closely monitored for 5 days following the diagnosis of the index case. The SAR of symptomatic SARS-CoV-2 infections among roommates was calculated.

RESULTS

Eighteen patients were identified as index cases with whom a total of 53 roommates had contact. Among these exposed roommates, secondary symptomatic SARS-CoV-2 infections occurred in 2 shared rooms, and the SAR within 5 days after the exposure from the index case was 5.7% (3/53).

CONCLUSIONS

The SAR of symptomatic SARS-CoV-2 infections in the largest tertiary children's hospital in Japan was not high in this study. Further studies are warranted to validate our findings and to establish effective isolation and surveillance strategies for SARS-CoV-2 in hospitalized children.

Pooling of samples to optimise SARS-CoV-2 detection in nasopharyngeal swabs and gargle lavage self-samples for covid-19 diagnostics and surveillance

BACKGROUND

Testing of pooled samples is an effective strategy for increasing testing capacity while saving resources and time. This study aimed to validate pooled testing and gather real-life data on its use for Covid-19 surveillance with a gargle lavage (GL) self-sampling strategy.

METHODS

Two-stage pooled testing with pools of 6 and 12 samples was used for preventive testing of an asymptomatic population and Covid-19 surveillance in Czech schools. Both GL and nasopharyngeal swabs were used for sampling.

RESULTS

In total, 61,111 samples were tested. The use of pooled testing for large-scale Covid-19 surveillance reduced consumable costs by almost 75% and increased testing capacity up to 3.8-fold compared to standard methods. RT-PCR experiments revealed a minimal loss of sensitivity (0-2.2%) when using pooled samples, enabling the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genes with Ct values >35. The minor loss of sensitivity was counterbalanced by a significantly increased throughput and the ability to substantially increase testing frequencies.

CONCLUSIONS

Pooled testing is considerably more cost-effective and less time-consuming than standard testing for large-scale Covid-19 surveillance even when the prevalence of SARS-CoV-2 is fluctuating. Gargle lavage self-sampling is a non-invasive technique suitable for sample collection without a healthcare worker's assistance.

Household Transmission Dynamics of Asymptomatic SARS-CoV-2-Infected Children: A Multinational, Controlled Case-Ascertained Prospective Study

BACKGROUND

Asymptomatic SARS-CoV-2 infection in children is highly prevalent but its acute and chronic implications have been minimally described.

METHODS

In this controlled case-ascertained household transmission study, we recruited asymptomatic children <18 years with SARS-CoV-2 nucleic acid testing performed at 12 tertiary care pediatric institutions in Canada and the United States. We attempted to recruit all test-positive children and 1 to 3 test-negative, site-matched controls. After 14 days' follow-up we assessed the clinical (ie, symptomatic) and combined (ie, test-positive, or symptomatic) secondary attack rates (SARs) among household contacts. Additionally, post-COVID-19 condition (PCC) was assessed in SARS-CoV-2-positive participating children after 90 days' follow-up.

RESULTS

A total of 111 test-positive and 256 SARS-CoV-2 test-negative asymptomatic children were enrolled between January 2021 and April 2022. After 14 days, excluding households with co-primary cases, the clinical SAR among household contacts of SARS-CoV-2-positive and -negative index children was 10.6% (19/179; 95% CI: 6.5%-16.1%) and 2.0% (13/663; 95% CI: 1.0%-3.3%), respectively (relative risk = 5.4; 95% CI: 2.7-10.7). In households with a SARS-CoV-2-positive index child, age <5 years, being pre-symptomatic (ie, developed symptoms after test), and testing positive during Omicron and Delta circulation periods (vs earlier) were associated with increased clinical and combined SARs among household contacts. Among 77 asymptomatic SARS-CoV-2-infected children with 90-day follow-up, 6 (7.8%; 95% CI: 2.9%-16.2%) reported PCC.

CONCLUSIONS

Asymptomatic SARS-CoV-2-infected children, especially those <5 years, are important contributors to household transmission, with 1 in 10 exposed household contacts developing symptomatic illness within 14 days. Asymptomatic SARS-CoV-2-infected children may develop PCC.

Differences in SARS-COV-2 seroprevalence in the population of Cusco, Peru

Background

The spread of the coronavirus disease 2019 (COVID-19) in Peru has been reported at the regional level, few studies have evaluated its spread at the provincial level, in which the mechanisms could be different.

Methods

We conducted an analytical, cross-sectional, multistage observational population study to assess the seroprevalence of SARS-COV-2 at the provincial and urban/rural levels in a high-altitude setting. The sampling unit was the household, including a randomly selected family member. Sampling was performed using a data collection sheet on clinical and epidemiological variables. Chemiluminescence tests were used to detect total anti-SARS-COV-2 antibodies (IgG and IgM simultaneously). The percentages were adjusted to the sampling design.

Results

The overall prevalence in the region of Cusco was 25.9%, with considerably different prevalence between the 13 provinces (from 15.9% in Acomayo to 40.1% in Canchis) and between rural (21.1%) and urban (31.7%) areas. In multivariable model, living in a rural area was a protective factor (adjusted prevalence ratio [aPR], 0.68; 95% confidence interval [CI], 0.61-0.76).

Conclusions

Geographic diversity and population density determine different prevalence rates, typically lower in rural areas, possibly due to natural social distancing or limited interaction with people at risk.

Timing of general anesthesia for pediatric patients recovering from COVID-19: a prospective cohort study

OBJECTIVE

To explore the timing of general anesthesia for pediatric patients who have recovered from novel coronavirus infection and summarize anesthesia-related complications.

METHODS

We summarized the perioperative management of children under 14 years of age who underwent general anesthesia in our hospital according to national epidemic prevention and control requirements. We compared the incidence of postoperative pulmonary complications within 2 weeks (Group A), 3-4 weeks (Group B), and 5-6 weeks (Group C) after COVID-19 recovery.

RESULTS

There were differences among the three groups in terms of decreased blood oxygen saturation (< 94%), secretions, and coughing during the PACU period. The risk of low blood oxygen saturation during PACU decreased as the time of COVID-19 recovery extended in the three groups. Compared to Group A, the risk of low blood oxygen saturation was lower in Group B. The presence of respiratory symptoms and a body temperature above 40℃ increased the risk of decreased blood oxygen saturation. The proportion of children aged 11-14 years and children with high fever experiencing decreased blood oxygen saturation during PACU was higher in Groups A and B. Among the three groups, children with respiratory symptoms and longer illness duration had a higher proportion of decreased blood oxygen saturation during PACU.

CONCLUSION

Pediatric patients who have recovered from COVID-19 for more than 2 weeks have a lower risk of postoperative complications after general anesthesia. For children with respiratory system symptoms or high fever, there is a higher risk of transient blood oxygen saturation decrease during PACU. For older children, those with high fever, respiratory system symptoms, or longer illness duration, it is recommended to appropriately extend the time from COVID-19 recovery to surgery.

Environmental and behavioral factors associated with household transmission of SARS-CoV-2 in children and adolescents

Objective

To analyze the association between risk behaviors and environmental factors and SARS-CoV-2 infection in children and adolescents in the family environment.

Methods

Cross-sectional study. A total of 267 children and adolescents aged 5-19 years who have contact with COVID-19-positive essential workers were tested between June and October 2020. Behavioral and environmental variables associated with SARS-CoV-2 infection were investigated. Association between these variables was performed using Poisson regression.

Results

SARS-CoV-2 prevalence was 25.1%. Following the confirmation of COVID-19 diagnosis of the index case, 92.1% of adults reported hand hygiene and 83.5% showed habits of respiratory etiquette. However, 12.7% wore masks in common areas of the residence before COVID-19. Sharing common objects was a risk factor for SARS-CoV-2 infection in the sample.

Conclusion

Sharing objects among family members was identified as a risk factor associated with SARS-CoV-2 infection in children and adolescents who lived with infected adults. There was high frequency of hand hygiene and low prevalence of mask use.

The Role of Children in Household Transmission of SARS-CoV-2 Across Four Waves of the Pandemic

BACKGROUND

It is important to understand the dynamics of SARS-CoV-2 transmission in close-contact settings such as households. We hypothesized that children would most often acquire SARS-CoV-2 from a symptomatic adult caregiver.

METHODS

This prospective cohort study was conducted from April 2020 to July 2022 in a low-resource, urban settlement in Brazil. We recruited families who brought their children to a public clinic. We collected nasopharyngeal and oral swabs from household members and tracked symptoms and vaccination.

RESULTS

In total, 1256 participants in 298 households were tested for SARS-CoV-2. A total of 4073 RT-PCR tests were run with 893 SARS-CoV-2 positive results (21.9%). SARS-CoV-2 cases were defined as isolated cases (N = 158) or well-defined transmission events (N = 175). The risk of household transmission was lower if the index case was a child (OR: 0.3 [95% CI: 0.16-0.55], P < .001) or was vaccinated (OR: 0.29 [95% CI: 0.1-0.85], P = .024), and higher if the index was symptomatic (OR: 2.53 [95% CI: 1.51-4.26], P < .001). The secondary attack rate for child index cases to child contacts was 0.29, whereas the secondary attack rate for adult index cases to child contacts was 0.47 (P = .08).

CONCLUSIONS

In this community, children were significantly less infectious to their household contacts than adolescents or adults. Most children were infected by a symptomatic adult, usually their mother. There was a double benefit of vaccination as it protected the vaccine from severe illness and prevented onward transmission to household contacts. Our findings may also be valid for similar populations throughout Latin America.

The role of children in transmission of SARS-CoV-2 variants of concern within households: an updated systematic review and meta-analysis, as at 30 June 2022

BackgroundMeta-analyses and single-site studies have established that children are less infectious than adults within a household when positive for ancestral SARS-CoV-2. In addition, children appear less susceptible to infection when exposed to ancestral SARS-CoV-2 within a household. The emergence of SARS-CoV-2 variants of concern (VOC) has been associated with an increased number of paediatric infections worldwide. However, the role of children in the household transmission of VOC, relative to the ancestral virus, remains unclear.AimWe aimed to evaluate children's role in household transmission of SARS-CoV-2 VOC.MethodsWe perform a meta-analysis of the role of children in household transmission of both ancestral SARS-CoV-2 and SARS-CoV-2 VOC.ResultsUnlike with the ancestral virus, children infected with VOC spread SARS-CoV-2 to an equivalent number of household contacts as infected adults and were equally as likely to acquire SARS-CoV-2 VOC from an infected family member. Interestingly, the same was observed when unvaccinated children exposed to VOC were compared with unvaccinated adults exposed to VOC.ConclusionsThese data suggest that the emergence of VOC was associated with a fundamental shift in the epidemiology of SARS-CoV-2. It is unlikely that this is solely the result of age-dependent differences in vaccination during the VOC period and may instead reflect virus evolution over the course of the pandemic.