Antibodies Last at Least 9 Months After COVID-19 Infection

Modeling showed 1 in 4 infected people pass the infection to a family member.

A recent study conducted by investigators from the Imperial College London, in collaboration with the University of Padova, has found that antibody levels remain high for at least 9 months after an infection with SARS-CoV-2, no matter if the individual was symptomatic or asymptomatic.

Results from the study were published in the journal Nature Communications.

"We found no evidence that antibody levels between symptomatic and asymptomatic infections differ significantly, suggesting that the strength of the immune response does not depend on the symptoms and the severity of the infection,” Ilaria Dorigatti, lead author on the study said. "However, our study does shows that antibody levels vary, sometimes markedly, depending on the test used. This means that caution is needed when comparing estimates of infection levels in a population obtained in different parts of the world with different tests and at different times."

For the study, the team of investigators tested more than 85% of the population of Vo’, Italy between February and March of 2020 for an infection with the SARS-CoV-2 virus. They then tested them again between May and November of 2020 for antibodies.

The team used 3 different assays to track the levels of antibodies in the residents.

Findings from the study showed that 98.8% of the participants that were infected between February and March showed detectable levels of antibodies in November. The investigators also saw no difference between those who had COVID-19 symptoms and those who were asymptomatic.

Additionally, they saw some cases of antibody levels increasing, which could suggest potential re-infections which boosted the immune system.

"It is clear that the epidemic is not over, neither in Italy nor abroad. Moving forward, I think that it is of fundamental importance to continue administering first and second vaccine doses as well as to strengthen surveillance including contact tracing,” Dorigatti said. “Encouraging caution and limiting the risk of acquiring SARS-CoV-2 will continue to be essential."