Humoral Immune Response to SARS-CoV-2 in Iceland
Study of 1,797 persons who had recovered from COVID-19 infection found that 91.1% of those who were tested were seropositive for antiviral antibodies, with titres increasing during the 2 months after diagnosis and then remaining on a plateau for the remainder of the study.
Source:
New England Journal of Medicine
SPS commentary:
An editorial discusses these findings in relation to other research that has pointed to rapid waning of antibody immunity, antibody responses being inversely correlated to disease severity, and even suggesting that asymptomatic infection could occur without seroconversion. It notes that this report at the population level however, captures insights on prevalence, fatality risk, and durability of immunity, with the most striking observation being that antibodies remained stable over the 4 months after diagnosis, a finding captured in a subgroup of longitudinally monitored subjects.
Although it is unclear , whether antibodies that persist confer protection and retain neutralizing or other protective effector functions that are required to block reinfection, , these new data point to the utility of antibody assays as highly cost-effective alternatives to PCR testing for population-level surveillance, which is critical to the safe reopening of cities and schools, and as biomarkers and possible effectors of immunity, i.e. useful tools that can be deployed now, until the arrival of of vaccines that will end the pandemic of Covid-19.