COVID: transmission from kids to adults

 Covid-19 outbreaks in childcare facilities in Salt Lake City suggest a potentially important role for child-to-adult transmission, even from asymptomatic or minimally symptomatic kids (see https://www.cdc.gov/mmwr/volumes/69/wr/mm6937e3.htm ) 

 

Details: 

-- overall, there were 17 childcare facilities in Utah with at least 2 confirmed Covid cases within a 14-day period. 

-- this report reflects detailed investigation and contact tracing from 3 facilities, from April 1 to July 10

 

-- 184 person, including 110 children had a known epidemiologic link to one of these 3 facilities  

-- 31 confirmed cases of Covid-19 occurred: 13 (42%) in children (mean age of 7, range of 0.2-16yo), 54% female  [confirmed cases had positive SARS-CoV-2 PCR test results]

    -- 9 of the children had mild cases, and 4 were asymptomatic 

 

Results: 

-- transmission was documented from these children to at least 12 (26%) of 46 non-facility contacts (confirmed or probable cases, the latter having compatible symptoms but no laboratory testing) 

-- one parent was hospitalized with Covid-19

-- among the 83 contacts of these 12 pediatric patients, 46 (55%) were nonfacility contacts, including 12 (26%) with confirmed Covid-19 and 5 with probable

    --6 cases occurred in mothers and 3 in siblings of the pediatric patients. 

-- transmission was observed from 2 of 3 children with confirmed asymptomatic Covid-19 

 

Commentary: 

-- older children (>10yo) have had documented transmission of SARS-CoV-2. Eg see https://www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6931-H.pdf finding high transmission rates in an overnight camp in Georgia, with attack rates in the 50% range 

--This current study rigorously documents the very probable transmission of SARS-CoV-2 from younger kids in daycare to household contacts, even from asymptomatic children

--a study in adults confirmed that there are lots of asymptomatic people, and they can have very high SAR-CoV-2 viral loads and maintain these high viral loads for a few weeks: see http://gmodestmedblogs.blogspot.com/2020/08/covid-asymptomatic-people-have-high.html (this blog references several others on asymptomatic adult patients)

-- this Utah study suggests that there probably should be widespread testing of child contacts of laboratory confirmed Covid-19 cases in childcare settings, including those who are asymptomatic 

-- we should also be encouraging children greater than 2 years old to wear masks, though this might be a tad difficult. And, others should wear masks, should have good hand hygiene, disinfecting of high touch surfaces, and strong encouragement to stay home when ill 

-- one issue here is that some staff members worked while their household contacts were ill with Covid-19 compatible symptoms, and one of the workers worked with mild symptoms

 

Limitations of the study: 

-- testing criteria basically were only for symptomatic persons, with symptoms of fever, cough and shortness of breath, and likely significantly underestimating cases and transmission 

-- guidance for contact tracing changed over the course of the study, and the number of asymptomatic contacts not tested overall was quite high, about 50% 

so, what are the implications of this study?

-- this study, as others, found that children had much less severe disease than what is found more often found in adults. 

    -- these mild URI-type symptoms will be increasingly difficult to differentiate from the many different viruses causing URIs in the colder weather (rhinoviruses, seasonal coronaviruses...)

    -- and, we know that young children average on the order of 5 URIs per winter (which i think means that they pretty much always have URI symptoms throughout the winter....)

    -- perhaps whenever a kid gets one of these frequent URIs, we should be testing the child for Covid and all of their contacts if Covid-positive. and institute appropriate quarantine procedures

        -- quarantining perhaps even those with minimal non-Covid URIs (and since people can have more than one viral URI at a time, and since there are many false negative Covid-PCR tests). Meaning that perhaps all with any URI symptoms (or minimal allergic symptoms that are indistinguishable from URI symptoms) should not go to these centers, both kids and adults [for blog on false negative tests: see http://gmodestmedblogs.blogspot.com/2020/05/covid-false-negative-pcr-results-over.html )

        -- which might significantly depopulate these centers in the upcoming cold weather, with all of the collateral damage on the financial state of the centers, the fate of the workers employed there, the need for working parents to remain home, etc etc). 

-- the key part here remains aggressive contact tracing (more so than was done in this study, where more than 1/2 the contacts were not tested)

    -- since it seems that asymptomatic young ones can transmit the disease to adults, that's a huge number of people

    -- which all means that we need to be prepared to do huge numbers of Covid tests in the upcoming months  

    -- and, which means that we as a country need to have a consistent public health policy for testing, using PPE, etc. Or those areas not doing so will be breeding grounds for the virus, which will then continue to spread there and elsewhere....

--we should not be just taking temperatures and assessing symptoms: not an adequate Covid screen (newer recommendations are reinforcing this), for a couple of reasons:

    --the index patient was a staff member in one of the facilities and was asymptomatic

    --the index patient in another facility was mildly symptomatic. and, not surprisingly, this and other studies have found that people with mild symptoms may not report them appropriately

-- and it raises the issue of doing routine Covid-19 testing in asymptomatic children in childcare facilities on a regular basis, since they clearly be can be asymptomatic vectors of disease both within the facility and home 

 

geoff

 

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