Question: Yesterday, I had to have some x-rays done at our local hospital. I told the tech that I had two negative antibody tests; he declared he’d had a positive antibody test three months ago, having had no symptoms. I asked him if he was able to transmit the virus, having had a positive result and his answer “Nobody knows!” Should I worry or hope that the hospital protocol of screening employees is appropriate? Thank you!

Answer: No need to worry! Here’s why:

• Current evidence shows that a person is infectious generally no more than 10 days after symptom onset. For a small proportion of individuals, the duration of infectivity may extend to 20 days after symptom onset (synthesized by CDC here and further described by CDC here). And we discussed the period of infectivity among asymptomatic people in our Q&A of 7/4, with evidence showing that asymptomatic people are generally infectious no more than 10 days after a positive test.
• Having antibodies does NOT mean that you have the virus or are able to transmit the virus! Testing positive for antibodies is different from testing positive for the virus; antibody tests tell you whether your body has circulating antibodies indicating previous infection while PCR/molecular tests identify active infection (Table 1).

Finally, growing stigma against people who have recovered from COVID-19 is yet another challenge we must confront. Such stigma hurts individuals, groups, and society as a whole. Among the many negative impacts of stigma, it can make curbing the pandemic much more difficult — it can make people more likely to hide symptoms, less likely to participate in contact tracing efforts, more likely to avoid seeking health care, and more! One of the key ways to confront stigma is to increase education and reduce misinformation. So please keep sharing this type of information with others!

Table 1. Different Types of COVID-19 Tests — Molecular, Antibody, and Antigen (from FDA)