Both the Pfizer and Moderna vaccines set off a persistent immune reaction which may offer protection against Covid-19 for several years, new research shows.
The findings add to growing evidence that most people immunised with mRNA vaccines may not need booster shots so long as the virus and its variants do not evolve much beyond their current forms.
The research, which was led by academics in Washington University, was published in the journal Nature.
Prof Kingston Mills, who studies immunology in Trinity College Dublin, said the research results were "great news," and strongly suggested mRNA vaccines offered long-term protection against the virus.
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Prof Mills said the findings would be “consistent” with vaccine data, and largely “is what we expected”.
“That’s all very well if the virus stays the same, even as it stands the virus has changed,” he said. Given the recent spread of the Delta variant, which is more transmissible even amongst those vaccinated, booster shots would likely be needed in the Autumn, the virologist said.
The study showed that the mRNA vaccines, such as Pfizer and Moderna, were “absolutely the Rolls-Royce” of vaccines. While it only took “a number of weeks” for manufacturers to refine vaccines to cover new variants, they then had to undergo tests, which took time, he said.
The US study sought to assess people’s long term immunity by studying specific cells in the lymph nodes. The study examined 41 people, eight of whom had previously been infected with Covid-19, and had received two doses of the Pfizer-BioNTech vaccine.
The researchers said it was difficult to predict exactly how long immunity from mRNA vaccines would last, and depended on the prevalence of new variants.
It noted people who were infected with the virus and later fully vaccinated saw a major boost in their antibody levels. – Additional reporting New York Times
