Booster for J&J shot may be needed
As Delta variant spreads, discussion arises whether J&J vaccines may need boosters, some experts are already taking them Slovíčka
Infectious disease experts are weighing the need for booster shots of the Pfzer/BioNTech or Moderna, mRNA-based vaccines for Americans who received Johnson & Johnson's one-dose vaccine due to the increasing prevalence of the more contagious Delta variant.
A few say they have already done so themselves, even without published data on whether combining two different vaccines is safe and effective or backing from U.S. health regulators. Canada and some European countries are already allowing people to get two different COVID-19 shots.
The debate centers on concerns over how protective the J&J shot is against the Delta variant first detected in India and now circulating widely in many countries. Delta, which has also been associated with more severe disease, could quickly become the dominant version of the virus in the United States.
There is no substantial data showing how protective the J&J vaccine is against the new variant. However, UK studies show that two doses of either the Pfizer/BioNTech or AstraZeneca vaccines are significantly more protective against the variant than one.
"There's no doubt that the people who receive the J&J vaccine are less protected against disease," than those who get two doses of the other shots, said Stanford professor Dr. Lin. "From the principle of taking easy steps to prevent really bad outcomes, this is really a no brainer."
The CDC is not recommending boosters, and advisors to the agency said there is not yet significant evidence of declining protection from the vaccines.
Jason Gallagher, an infectious diseases expert, recently received a Pfizer dose at the Philadelphia vaccine clinic. He got the J&J vaccine in a clinical trial in November.
Gallagher said he was concerned about the UK showing lower efficacy against the Delta variant for people who received one vaccine dose.
"While the situation has gotten so much better in the U.S., the Delta variant that's spreading ... and really quickly taking over in the U.S. looks a little more concerning in terms of the breakthrough infections with the single-dose vaccines, so I took the plunge."
Cases, hospitalizations and deaths have plummeted in the United States with 56% of the adult population fully vaccinated.
J&J said it is testing whether the immune response from its vaccine is capable of neutralizing the Delta variant in a laboratory setting, but no data is available yet.
The mRNA vaccines showed efficacy rates around 95% in large U.S. trials, while J&J's vaccine was 66% effective in preventing moderate-to-severe COVID-19 globally when more contagious variants were circulating.
Text pochází z agentury Reuters
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