Booster vaccines may well offer good protection against the Omicron variant, the experts behind a major new study have suggested.
A team that studies the effects of third doses has said that the body’s T cell immune response after a booster injection is such that it may provide protection against hospitalization and death.
The study also confirms the UK’s decision to offer Pfizer or Moderna as a third injection, with mRNA injections leading to the most significant increase in immunity levels.
Professor Saul Faust, head of the trial and director of the NIHR Clinical Research Center at Southampton University Hospital NHS Foundation Trust, said the CovBoost study had shown that six different vaccines are safe and effective as doses of reminder for people who have already received two doses of AstraZeneca or Pfizer / BioNTech.
The six vaccines tested as a third dose were AstraZeneca, Pfizer / BioNTech, Moderna, Novavax, Janssen (made by Johnson and Johnson) and CureVac (which ceased production).
“All of the vaccines in our study show a statistically significant boost … very high RNA (Pfizer and Moderna), but also very effective boosts from Novavax, Janssen and AstraZeneca,” said Professor Faust.
He added that the vaccines worked well against existing variants, although Omicron was not tested in the study.
However, experts believe that T cell immunity – which has been studied alongside antibodies in research – could play an important role in fighting the variant as well.
T cells play a key role and work alongside antibodies in the immune system to target viruses.
âEven though we don’t fully understand its relationship to long-term immunity, T cell data shows us that it appears to be broader against all variant strains, giving us hope that a variant strain of the virus might be able to be manipulated, certainly for hospitalization and death if not prevention of infection, by current vaccines, âProf. Faust said.
He said the T-cell response was not focused solely on the spike protein, but “recognized a much wider range of antigens that mightâ¦ be common to all of the variants.”
Asked specifically about Omicron, he said: “Our hope as scientists is that the protection against hospitalization and death remains intact.”
Samples from the study have now been forwarded to the British Health Safety Agency (UKHSA) to examine how well the Omicron variant can be neutralized by vaccines.
Jonathan Ball, professor of molecular virology at the University of Nottingham, said of the new research: âThis is a fantastic study and it’s great to finally see the data that has undoubtedly been essential. to decide on the UK vaccine booster approach.
âThe data clearly shows that all of the boosters improved at least one aspect of your Covid immunity, and the side effects were, overall, mild.
âThe data also shows that an mRNA booster – like Moderna or Pfizer – provided the best overall boost, whether your first doses were mRNA or (AstraZeneca).
âThe fact that the mRNA vaccine boosters have resulted in a marked increase in antibodies and T cells is great news, especially now, as our attention has been drawn to the emergence of the Omicron variant.
“We still don’t know how this boost in immunity translates into protection, especially against serious illnesses, but I am still confident that our vaccines will continue to provide the protection we need.”
The new CovBoost trial, published in The Lancet, looked at 2,878 people aged 30 and over who were boosted 10 to 12 weeks after their initial two-dose vaccination.
Overall, there were 13 different groups testing the boosters or acting as controls, with the controls given the meningitis vaccine.
Immunity was then assessed after 28 days, with experts saying more data will be released in the future on immunity results three months and one year after receiving boosters.
More data will also be released early next year to determine if a longer period between the second and third dose improves response.
The seven vaccines posed no safety concerns, according to the study, with fatigue, headaches and arm pain being the most commonly reported problems.
Professor Faust said: âIt is really encouraging that a wide range of vaccines, using different technologies, have advantages as a third dose for AstraZeneca or Pfizer / BioNTech.
“This gives confidence and flexibility in the development of recall programs here in the UK and around the world, with other factors such as supply chain and logistics also at play.”
Looking at the antibody levels in the trial, people who received two doses of AstraZeneca initially had booster responses that were between 1.8 times and 32.3 times higher depending on the booster vaccine used. .
After two doses of Pfizer, the range was 1.3 times higher to 11.5 times higher.
The authors said these ratios should be interpreted with caution as they relate to immune response rather than actual protection against disease.