Health Editor’s Note: Immunity against SARS-CoV-2 may not be long lasting in people who have a mild illness. The majority of those who have coronavirus fall into that category. We can get the common cold, which is a coronavirus, over and over again, because we do not develop a lasting immunity. Generally, if we contract (or are vaccinated for) the viruses of measles, mumps, rubella, chicken pox, we will develop a life-long immunity to those viruses.
What is revealed in this study is that the immunity levels, measured in the blood, decrease at a fairly rapid rate after the initial infection. Since this study has only gone on for 90 days it is unsure if the decrease in antibodies will continue or if some antibodies will remain for long term and if they will be strong enough (longer lived) to fight further COVID-19 infections….Carol
Rapid Decay of Anti–SARS-CoV-2 Antibodies in Persons with Mild Covid-19
July 21, 2020
A recent article suggested the rapid decay of anti–SARS-CoV-2 IgG in early infection,1 but the rate was not described in detail. We evaluated persons who had recovered from Covid-19 and referred themselves to our institution for observational research. Written informed consent was obtained from all the participants, with approval by the institutional review board. Blood samples were analyzed by enzyme-linked immunosorbent assay (ELISA) to detect anti–SARS-CoV-2 spike receptor-binding domain IgG.2 The ELISA was further modified to precisely quantify serum anti–receptor-binding domain activity in terms of equivalence to the concentration of a control anti–receptor-binding domain monoclonal IgG (CR3022, Creative Biolabs).
Infection had been confirmed by polymerase-chain-reaction assay in 30 of the 34 participants. The other 4 participants had had symptoms compatible with Covid-19 and had cohabitated with persons who were known to have Covid-19 but were not tested because of mild illness and the limited availability of testing. Most of the participants had mild illness; 2 received low-flow supplemental oxygen and leronlimab (a CCR5 antagonist), but they did not receive remdesivir. There were 20 women and 14 men. The mean age was 43 years (range, 21 to 68).