Pfizer and BioNTech announced Thursday that they are developing a version of the coronavirus vaccine that targets the highly contagious variant Delta, which is widespread in nearly 100 countries. Both companies plan to begin clinical trials of the vaccine in August.
Pfizer and BioNTech also reported promising results from the studies of those who received them. Third inoculation of the original vaccine.. The two companies said that boosting immunization six months after the second dose of the vaccine increased the potency of the antibody against the original virus and beta mutants by a factor of 5 to 10.
Vaccine efficacy may decline six months after immunization, the companies said in a news release, which may require booster immunization to fend off viral variants.
The data has not been published and has not been peer reviewed. The vaccine manufacturer said it plans to submit the findings to the Food and Drug Administration within the next few weeks as a step towards obtaining approval for booster shots.
However, the claims of both companies were inconsistent with other studies, and some experts disagreed with the claim that boosters were needed.
Dr. Celine Gounder, an infectious disease specialist at the Bellevue Hospital Center in New York, said: “In fact, many of us are wondering if we need a booster.”
Federal agencies also sounded suspicious notes Thursday night. In general, fully vaccinated Americans do not need booster shots at this time, the FDA and the US Centers for Disease Control and Prevention said in a joint statement.
“If science proves that a booster effect is needed, we are ready for booster doses,” the authorities said.
The Delta variant, first identified in India, is about 60% more contagious than Alpha, the version of the virus that hit most of the UK and Europe earlier this year, and is probably twice as contagious as the original coronavirus. It is believed that there is.
Delta variants are currently promoting the development of unvaccinated populations in countries such as Malaysia, Portugal, Indonesia and Australia.Delta too Currently the predominant variant in the United States, CDC reported this week.
Until recently, infectious diseases in the United States have been flat at the lowest levels since the early days of the pandemic. Virus-related hospitalizations and deaths continue to decline, but new infections may be on the rise.
It is not yet clear how responsible the variant is. Delays and rapid resumption of vaccination also play a role.
Citing data from Israel, Pfizer and BioNTech suggested that “the effectiveness of the vaccine in the prevention of both infections and symptomatic diseases diminished six months after vaccination.” Focusing on the rise of Delta Air Lines and other variants, the two companies said that “a third dose may be required within 6-12 months of complete vaccination.”
Israeli health officials estimate that complete vaccination with Pfizer-BioNTech provides only 64% efficacy against delta mutants. (Effectiveness against the original virus is over 90%.)
But Israeli quote Inconsistent with many other studies The vaccine has been found to be very effective in preventing infections — for all variants. In one recent study, mRNA vaccines, such as Pfizer, provoke a sustained immune response in the body, Protect for years from coronavirus..
John Moore, a virologist at Weil Cornell Medicine in New York, said: “If it’s the right time to use boosters here, the decision is not their judgment.”
The two companies have described plans to develop a new vaccine against Delta as a kind of backup effort in the event of a failed booster immunization of the original vaccine. The new vaccine targets the entire speplomer, not just part of it, and the first batch has already been manufactured.
Delta variants pose challenges to the immune system.In the journal Nature, French researchers reported new evidence for the Delta variant on Thursday. Can partially avoid the body’s immune response Due to changes in peplomer on the surface that make it difficult for antibodies to attack.
The team analyzed blood samples from 59 people who received the first and second doses of the vaccine. Blood samples from only 10% of people immunized with a single dose of AstraZeneca or Pfizer-BioNTech vaccine were able to neutralize delta and beta variants in laboratory experiments.
“A single dose of Pfizer or AstraZeneca was inadequate or not at all efficient for beta and delta mutants,” the researchers concluded. While data from Israel and the United Kingdom widely support this finding, these studies also suggest that a single dose of the vaccine is sufficient to prevent hospitalization and viral death.
However, the second dose improved the efficacy to 95%... There was no significant difference in the levels of antibodies elicited by the two vaccines.
“Twice the mRNA vaccine provides very good protection against serious illness, hospitalization and death for both mutants,” said Dr. Gounder.
The researchers also examined blood samples from 103 people infected with the coronavirus. delta Studies have shown that it was much less sensitive than alpha to samples from this group of unvaccinated people.
A single dose of the vaccine significantly increased sensitivity, suggesting that people who recover from Covid-19 need to be vaccinated to dodge some mutants.
In summary, the results show that two vaccinations are strongly protective against all mutants, as well as one dose to people who have recovered from Covid-19 and have some degree of innate immunity. It suggests that.
Some experts have also questioned the debate about boosters for Americans, but many worlds have not even received a single dose yet.
“It’s impossible to ignore the global situation,” said Natalie Dean, a biostatistician at Emory University in Atlanta. “It’s hard to imagine getting a third vaccination when there are front-line workers treating unvaccinated Covid patients.”
Everyone who is not vaccinated offers an additional opportunity to mutate into a variant that is dangerous to the virus, Dr. Gounder said.
“If we are worried about mutants, our best protection is to vaccinate people around the world, and even here to vaccinate people here in the United States for a third mRNA vaccine. It ’s not about storing a lot of vaccines. ”
Citing the Delta variant, Pfizer pursues booster shots and new vaccines
Source link Citing the Delta variant, Pfizer pursues booster shots and new vaccines