Coronavirus immunity may only last within a few months, according to a study in the UK about the longevity of potential coronavirus vaccines.
The team from Kings College London discovered that antibody responses to the coronavirus can reach its top performance after onset of symptoms. However, coronavirus immunity may wane after a little as two months.
The study was published Saturday on preprint server MedRxiv and not yet peer-reviewed. The researchers evaluated the antibody levels of Covid-19 patients, including 64 individuals and six health-care workers at Guy’s and St Thomas’ NHS foundation trust between March and June. The study examined 31 other members of staff who volunteered to undergo regular antibody tests.
Findings showed that 60% of the patients examined in the study manifested a “potent” level of antibodies after an average of 23 days following first onset of symptoms. However, only 16.7% revealed that level of antibodies 65 days after the initial signs of symptoms.
The researchers reported that antibody levels were higher in patients who had more severe disease, although the reason is uncertain. Meanwhile, some patients who produced antibodies were asymptomatic.
The study revealed that the antibody response to coronavirus was not different from that of SARS (severe acute respiratory syndrome) and seasonal flu-like coronaviruses. With these diseases, one's antibody response tends to “wane over time, from as little as 12 weeks to 12-34 months after infection.”
Katie Doores from KCL’s School of Immunology & Microbial Sciences, who led the study, explained that the antibody responses present in the blood are diminishing after infection. She recommends additional research to identify the level of antibodies needed for protection from infection.
“We need to continue to measure antibody responses in these individuals to see if antibody titres continue to drop or plateau to a steady state,” she said. Antibody titres are the existence and amount of antibodies within a person’s blood.
The team also studied how much protection people who recovered from Covid-19 have from subsequent reinfection as well as the durability of any coronavirus vaccine.
According to the World Health Organization, people who recover from Covid-19 may get the coronavirus again. They mention similar studies that suggest coronavirus immunity may last only a few months.
Dr. Maria Van Kerkhove, head of the WHO’s emerging diseases unit, noted that patients “do mount some level of an immune response.”
During a news conference at WHO's headquarters in Geneva, she noted that, “what we don’t know is how strong that protection is and for how long that protection will last.”
“So there are a number of studies under way that are trying to answer these questions,” she added.
Coronavirus vaccine
Dr. Anthony Fauci expressed his concern about how long the effectiveness of a coronavirus vaccine is.
He said that if Covid-19 persists like other coronaviruses, “it likely isn’t going to be a long duration of immunity.”
“When you look at the history of coronaviruses, the common coronaviruses that cause the common cold, the reports in the literature are that the durability of immunity that’s protective ranges from three to six months to almost always less than a year,” said Fauci, director of the National Institute of Allergy and Infectious Diseases, said during an interview with JAMA Editor Howard Bauchner.
“That’s not a lot of durability and protection.”
Meanwhile, the National Institutes of Health has been accelerating work with biotech firm Moderna on a potential Covid-19 vaccine.
