Early Seroprevalence Study showed 6-24x more cases of COVID-19 than counted by antigen tests: JAMANETWORK

This study, from JAMANETWORK on July 17, looked at blood antibody tests done in several large cities in late March of this year. The astounding finding: between 6 and 24 times more patients had antibodies than had been counted by nasopharyngeal swab testing for SARS-COV-2:

In this cross-sectional study of 16 025 residual clinical specimens, estimates of the proportion of persons with detectable SARS-CoV-2 antibodies ranged from 1.0% in the San Francisco Bay area (collected April 23-27) to 6.9% of persons in New York City (collected March 23-April 1). Six to 24 times more infections were estimated per site with seroprevalence than with coronavirus disease 2019 (COVID-19) case report data.

JAMA Intern Med. Published online July 21, 2020. doi:10.1001/jamainternmed.2020.4130

This study has been widely reported recently. Its finding, that an average of ten to twelve times more patients with antibodies were present in each city than had been counted by antigen testing, has not been accounted for.

The conclusion is that many people either had asymptomatic infection or never went to be tested when they had symptoms. This has implications for preventive measures: everyone should be trying to prevent catching this disease all the time, even when they are not around people known to have been infected.

This means that you should be wearing a mask whenever you are around people you don’t know intimately. Even those you know well are potential vectors of disease: every non-household member and even those in your own household.

Previous studies have found ten to twenty percent of household contacts of people with proven COVID-19 become infected within ten days after the virus has been detected. What happens after ten days is unknown.

There have been very few reports of infections among children under ten, but this population has not been well-studied. If schools open next month, we should soon find out how many children have it and how well they pass it on. I would be extremely cautious about contacts with small children.

Children over ten years of age are likely to be just as infectious as adults. This age group includes a large proportion of school children– everyone in fifth grade and above. The vast majority of them will not get sick, even when they are infected, but they will be efficient vectors of disease to their parents, grandparents, schoolteachers, and staff.

The risks of open schools in the USA, with its environment of rapidly expanding infections, are great. For the last week or so, every day has brought over 50,000 new cases, and every day over a thousand people die. The actual number of new cases each day, with a broken testing system, is completely unknown.

Only in a state like Vermont would opening schools for in person attendance be even minimally acceptable.