Over the weekend, a study was released on the longevity of COVID19 antibodies in New York. This is important in regards to the effectiveness of vaccines.
This new study just focused on symptomatic and confirmed COVID19 cases. Bottom line? Antibodies were found to last at LEAST 3 months (the study was only 3 months long). More details: Scientists followed 19,763 hospital employees who tested positive for COVID19. After 52 days of symptom onset, the scientists took a blood draw to test how many antibodies people had: 7% made low levels of antibodies; 22% made medium; and 70% made high levels of antibodies. Then the scientists took a blood draw 82 days after symptom onset. Antibody counts were relatively stable. Only one person had zero antibodies.
This study both compliments and contradicts a smaller study conducted in China (Long et al., I posted earlier). Their bottom line? Antibodies lasted at least 8 weeks, but not for everyone. More details: Among symptomatic patients, 84% had antibodies during the first follow-up and, of those, 87% had stable antibodies at the second follow-up.
So which study is “correct”? The NY authors state that the discrepancy between studies is likely due to evaluating different types of antibodies. ALSO it typically takes hundreds (if not thousands) of studies to clearly see the full story. Replication among different populations is key to make generalizations. However, the first few studies gives us an initial peak into biological mechanisms.
So we know that the antibodies fights off re-infection among primates and we know that transferring plasma among humans also reduces virus replication. We also know that antibodies from other coronaviruses (like MERS and SERS) last 2-3 years. This NY study will continue to collect information on the employees to continue to track antibody responses over time. I look forward to seeing their follow-up results.
Love, your local epidemiologist
Data sources: Figures by me using data from the following two studies:
Wajnberg et al., SARS-CoV-2 infection induces robust, neutralizing antibody responses that are 2 stable for at least three month. 2020; Q. X. Long et al., Clinical and immunological assessment of asymptomatic SARS-CoV-2 infections. Nat Med, (2020).