A large study from Spain showed that antibodies can disappear weeks after people have tested positive, causing some to question how possible it will be to attain herd immunity.
A study published in medical journal Lancet showed 14% of people who tested positive for antibodies no longer had antibodies weeks later.
“At present, herd immunity is difficult to achieve without accepting the collateral damage of many deaths in the susceptible population and overburdening of health systems,” the report reads.
Herd immunity is when enough of a population becomes immune to a disease through vaccine or already getting sick to make the spread unlikely between people in the community, according to the Centers for Disease Control and Prevention. Herd immunity also protects newborns and people who can’t be vaccinated because it helps decrease person-to-person spread, the CDC said.
The study was conducted from April 27 to May 11 and involved 61,075 participants in Spain who answered a questionnaire on COVID-19 symptoms, received an antibody test, and donated a blood sample for more testing if they agreed.