Minal Amin

A better understanding of SARS-CoV-2 transmission from children and adolescents is crucial for informing public health mitigation strategies. We conducted a retrospective cohort study among household contacts of primary cases defined as children and adolescents aged 7⍰19 years with laboratory evidence of SARS-CoV-2 infection acquired during an overnight camp outbreak. Among household contacts, we defined secondary cases using the Council of State and Territorial Epidemiologists definition. Among 526 household contacts of 224 primary cases, 48 secondary cases were identified, corresponding to a secondary attack rate of 9% (95% confidence interval [CI], 7%–12%). Our findings show that children and adolescents can transmit SARS-CoV-2 to adult contacts and other children in a household setting.

An estimated 1 in 150 infants is born each year with congenital cytomegalovirus (CMV); nearly 1 in 750 suffers permanent disabilities. Congenital CMV is the result of a pregnant woman becoming infected with CMV. Educating pregnant women about CMV is currently the best approach to prevention. Limited research is available on how to effectively communicate with women about CMV. We conducted formative research on fear appeals theory-based messages about CMV and prevention with U.S. women. Fear appeal theories suggest that message recipients will take action if they feel fear. First, we conducted in-depth interviews (N = 32) with women who had young children who tested positive for CMV. Second, we conducted eight focus groups (N = 70) in two phases and two cities (Phase 2: Atlanta, GA; Phase 3: San Diego, CA) with pregnant women and non-pregnant women who had young children. Few participants knew about CMV before the focus groups. Participants reviewed and gave feedback on messages created around fear appeals theory-based communication concepts. The following concepts were tested in one or more of the three phases of research: CMV is severe, CMV is common, CMV is preventable, CMV preventive strategies are similar to other behavior changes women make during pregnancy, CMV preventive strategies can be incorporated in moderation to reduce exposure, and CMV is severe but preventable. Participants recommended communicating that CMV is common by using prevalence ratios (e.g., 1 in 150) or comparing CMV to other well-known disabilities. To convey the severity of CMV, participants preferred stories about CMV along with prevention strategies. Participants also welcomed prevention strategies when it included a message about risk reduction. In general, participants said messages were motivating, even if they felt that it could be difficult to make certain behavior changes. Findings from this research can contribute to future efforts to educate pregnant women about CMV, especially regarding use of fear appeals-based messages. Pregnant women may face certain challenges to practicing prevention strategies but, overall, are motivated make changes to increase their chances of having a healthy baby.

To better understand potential transmission risks from contact with the body fluids of children, we monitored the presence and amount of CMV shedding over time in healthy CMV-seropositive children. Through screening we identified 36 children from the Atlanta, Georgia area who were CMV-seropositive, including 23 who were shedding CMV at the time of screening. Each child received 12 weekly in-home visits at which field workers collected saliva and urine. During the final two weeks, parents also collected saliva and urine daily. Prevalence of shedding was highly correlated with initial shedding status: children shedding at the screening visit had CMV DNA in 84% of follow-up saliva specimens (455/543) and 28% of follow-up urine specimens (151/539); those not shedding at the screening visit had CMV DNA in 16% of follow-up saliva specimens (47/303) and 5% of follow-up urine specimens (16/305). Among positive specimens we found median viral loads of 82,900 copies/mL in saliva and 34,730 copies/mL in urine (P = 0.01), while the viral load for the 75th percentile was nearly 1.5 million copies/mL for saliva compared to 86,800 copies/mL for urine. Younger age was significantly associated with higher viral loads, especially for saliva (P < 0.001). Shedding prevalence and viral loads were relatively stable over time. All children who were shedding at the screening visit were still shedding at least some days during weeks 11 and 12, and median and mean viral loads did not change substantially over time. Healthy CMV-seropositive children can shed CMV for months at high, relatively stable levels. These data suggest that behavioral prevention messages need to address transmission via both saliva and urine, but also need to be informed by the potentially higher risks posed by saliva and by exposures to younger children.

Congenital cytomegalovirus (CMV) is the leading infectious cause of birth defects in the United States. To better understand factors that may influence CMV transmission risk, we compared viral and immunological factors in healthy children and their mothers. We screened for CMV IgG antibodies in a convenience sample of 161 children aged 0-47 months from the Atlanta, Georgia metropolitan area, along with 32 mothers of children who screened CMV-seropositive. We assessed CMV shedding via PCR using saliva collected with oral swabs (children and mothers) and urine collected from diapers using filter paper inserts (children only). CMV IgG was present in 31% (50/161) of the children. Half (25/50) of seropositive children were shedding in at least one fluid. The proportion of seropositive children who shed in saliva was 100% (8/8) among the 4-12 month-olds, 64% (9/14) among 13-24 month-olds, and 40% (6/15) among 25-47 month-olds (P for trend = 0.003). Seropositive mothers had a lower proportion of saliva shedding (21% [6/29]) than children (P < 0.001). Among children who were shedding CMV, viral loads in saliva were significantly higher in younger children (P one million copies/mL) were only found in children's saliva (31% of those shedding); children's urine and mothers' saliva specimens all had fewer than 100,000 copies/mL. Low IgG avidity, a marker of primary infection, was associated with younger age (p = 0.03), higher viral loads in saliva (p = 0.02), and lower antibody titers (p = 0.005). Young CMV seropositive children, especially those less than one year-old may present high-risk CMV exposures to pregnant women, especially via saliva, though further research is needed to see if this finding can be generalized across racial or other demographic strata.

Young, healthy children shedding cytomegalovirus (CMV) in urine and saliva appear to be the leading source of CMV in primary infection of pregnant women. We screened 48 children 6 months – 5 years old for CMV IgG and measured levels of CMV IgG, IgM and IgG avidity antibodies, frequency of CMV shedding, and viral loads in blood, urine, and saliva. Thirteen of the 48 children (27%) were CMV IgG positive, among whom 3 were also CMV IgM positive with evidence of recent primary infection. Nine of the 13 seropositive children (69%) were shedding 102-105 copies/ml of CMV DNA in one or more bodily fluid. Among seropositive children, low IgG antibody titer (1:20–1:80) was associated with the absence of shedding (p = 0.014), and enrollment in daycare was associated with the presence of CMV shedding (p = 0.037). CMV antibody profiles correlated with CMV shedding. The presence of CMV IgM more often represents primary infection in children than in adults. Correlating antibodies with primary infection and viral shedding in healthy children adds to the understanding of CMV infection in children that can inform the prevention of CMV transmission to pregnant women.