A woman in a protective face mask walks through Brixton Market in south London while Britain remains locked to curb the spread of the coronavirus.
Victoria Jones | PA pictures via Getty Images
Immunity to Covid-19 could last only a few months, according to a British study that raises doubts about the longevity of potential coronavirus vaccines.
Antibody responses to the coronavirus can peak three weeks after symptoms first appear, but decrease after only 2-3 months, researchers at Kings College London noted.
The study, which was released on the preprint server MedRxiv on Saturday and has not yet been reviewed by experts, examined the antibody levels of 64 patients and six healthcare workers at Guy and St. Thomas̵
The researchers found that levels of antibodies that can fight the coronavirus peaked three weeks after symptoms appeared, but then decreased. While 60% of the subjects tested in the study had a “strong” antibody level after an average of 23 days after the first onset of symptoms, only 16.7% of the subjects tested had this “strong” level 65 days after the first signs of symptoms the antibody.
Antibody levels were higher in patients with more severe disease, although it is not clear why, KCL found and some individuals who developed antibodies were asymptomatic.
The researchers found that their study found that the antibody response to Covid-19 was similar to that of other human coronaviruses, such as SARS (Severe Acute Respiratory Syndrome) and seasonal coronaviruses, which are associated with colds and which tend to have an individual’s antibody response , “decrease over time from just 12 weeks to 12-34 months after infection.”
The study was conducted by Dr. Katie Doores from the KCL School of Immunology & Microbial Sciences. In relation to the research, she said that the circulating antibody responses to SARS-CoV-2 (or “severe acute respiratory syndrome coronavirus 2” – the virus that causes Covid-19 disease) in the blood decrease after infection and that this will decrease further Research is needed to determine the amount of antibodies required to protect against infection.
“We still need to measure antibody responses in these individuals to see if antibody titers continue to drop or reach a plateau in a stable state,” she said. Antibody titers relate to the presence and amount of Antibodies in a person’s blood.
Research questions how much protection people who had the coronavirus have from subsequent reinfection and how durable a potential vaccine is.
Officials from the World Health Organization said Monday that patients recovering from Covid-19 may get the coronavirus again, and cited similar studies suggesting that immunity may decline after a few months.
Dr. Maria Van Kerkhove, head of the WHO’s emerging diseases department, said that patients “develop a certain immune response”.
At a press conference at the organization’s headquarters in Geneva, she added: “We don’t know how strong this protection is and how long this protection lasts.”
“So there are a number of studies that are trying to answer these questions,” she said.
A peer-reviewed study published last week in Lancet’s medical journal claimed that Covid-19 antibodies “were not sufficient in the Spanish population to guarantee herd immunity”. This refers to when a population can have some exposure to the virus in order to build immunity among the general population.