Protective immunity is not a guarantee
The antibody titers are peaking at ≈1 month after symptom onset. The SARS patients were tested positive for antibodies to SARS for up to 3 years. Was the level of antibody sufficient? What does that mean for a current pandemic?
UK’s National COVID Testing Scientific Advisory Panel, published preliminary data to discuss whether individuals recovered from COVID19 have detectable antibodies in the blood. The presence of antibodies and the titers signal protection against possible reinfection.
Samples of confirmed COVID19 patients were tested for IgM and IgG levels. According to this paper, an infected person with confirmed positive PCR test for COVID-19 infection, experience rises in IgM and IgG levels during acute infection. After the initial recovery, the high levels of IgG persist for some time, and the patient is presumably immune for reinfection during that period.
Best case scenario: antibody-positivity and antibody titers confer protective immunity. And the level of antibodies is sufficient and lasting.
The IgG levels to COVID-19 were detected in all tested individuals (31) after ten days. IgG titers rose during the first three weeks and began to fall by eight weeks, but remained above the detection threshold. Sever…
