Covid-19 survivors may only need one injection, experts have suggested, after two studies found that those who already had the virus after the vaccine had a much higher diagnostic response than the those who were not infected.
In a study published online late Monday, researchers recommended that only one dose of the vaccine should be given to people who have tested positive for Covid-19.
“I think one vaccine should be enough,” Dr. Florian Krammer, a pathologist at Mount Iai’s Icahn School of Medicine and author of the study, told the New york times.
“This would also relieve individuals from unnecessary pain when they received the second dose, and would save additional doses of vaccine,” he said.
The study monitored the immune response of 109 individuals who had received the Pfizer-BioNTech or Moderna vaccine, both of which are based on mRNA technology.
Of these volunteers, 68 had never been infected with Covid-19 and 41 had previously been positive.
A “stronger” antibody response – 10 to 20 times higher – was seen in those infected with the virus compared to those not on Covid. In some cases this response was even higher than the level of protection created in those who were never infected after two doses of the vaccine.
This study also found that those previously infected with Covid-19 reported more common side effects.
Researchers evaluated post-vaccination symptoms in 231 individuals, including 83 who had previously tested positive for Covid-19 and 148 who did not.
People in each group reported pain at the injection site after the first vaccine dose. But those infected with Covid were more likely to report obesity, headaches and colds.
In a second study – which, like the first, was published online and not peer-reviewed – researchers at the University of Maryland in Baltimore came to similar conclusions.
The team studied antibody responses to a single dose of the Moderna and Pfizer-BioNTech vaccine in 59 health care workers. They reported a “statistically higher” antibody response in those who had been exposed to the virus before.
The report stated: “Our findings generally suggest that the following strategy is evidence-based: a) a single dose of vaccine for patients who have laboratory-tested Covid-19 ; and b) patients who have undergone laboratory-confirmed Covid-19 may be placed lower on the vaccine priority list. “
However, both studies have small numbers of people and some experts warn that much more research is needed before policy changes can be introduced.
Said John Wherry, director of the University of Pennsylvania Institute of Psychology New york times data investigating whether these antibodies were able to stop the virus from reproducing are needed.
“Just because an antibody binds to part of the virus doesn’t mean it’s going to protect you from being caught,” he said.
Dr Wherry also noted that it is difficult to challenge the introduction of a scheme where those who had previously received a single dose. “Documentation that becomes a potentially dangerous public health issue,” he said.
Lawrence Young, professor of molecular oncology at the University of Warwick, said further studies should be done.
“If future work can confirm this high level of immunity following a single mRNA vaccine in this group of people, this could become an operational option when there are concerns about vaccine supply. , “said Dr Young.
Eleanor Riley, professor of vaccination and infectious disease at the University of Edinburgh, said: “These data show that the vaccines effectively stimulate the immunity that causes infection.”
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