World leaders are straining health professionals on the COVID-19 vaccine mix amid growing concerns about delta mutants


Barcelona — German Chancellor Angela Merkel did it. So did Canada’s Prime Minister Justin Trudeau and Italy’s Prime Minister Mario Draghi. They mixed the COVID-19 vaccine, contrary to the advice of the Health Organization, after suspicions about the efficacy of the AstraZeneca version against the delta mutant began to spread.

In what appears to be a growing trend across Europe, the three leaders first received the adenovirus vaccine (AstraZeneca) and then switched to the second mRNA. Merkel and Trudeau took the second Modana COVID jab, and Draghi chose Pfizer. I overlooked advice from agencies that warn against treating it as compatible, such as the Centers for Disease Control and Prevention.

Mixing and matching different types of vaccines (currently unapproved “non-adaptive” practices by the World Health Organization) is now a common practice in 15 countries in Canada and Europe, raising concerns. It is starting to gain momentum in the United States. Whether the Johnson & Johnson vaccine provides strong enough protection against the Delta variant.

However, there are many questions about the safety and effectiveness of this approach.

“We have evidence-a vague, muddy fog. It’s like a fog of war,” Dr. Eric Fagledin, a senior researcher at the Federation of American Scientists, told Yahoo News.

Justin Trudeau, left

Canada’s Prime Minister Justin Trudeau vaccinated AstraZeneca in Ottawa in April. (Adrian Wild / CP / Bloomberg via Getty Images)

Daniel Lopez Akna, a former WHO crisis manager based in Spain, where DPT vaccine doses are endemic, agreed that there is too little evidence to show whether this practice makes sense.

“In terms of the evidence needed to make a sound decision, we must accept that we are in the gray area,” López-Acuna told Yahoo News.

On Thursday, the European Center for Disease Prevention and Control (ECDC) report It found that mixed doses could produce a “robust response” to COVID-19.

“Evidence from studies of heterogeneous (” mixed and match “) vaccination is: [AstraZeneca] And the mRNA vaccine is powerful [antibody] It is a response to SARS-CoV-2 and induces a higher T cell response than homologous combinations, “the report states.

“There is a good immune response to such a combination,” said Karam Adel Ali of Policy. ECDC Infectious Disease Expert, “The mix-and-match schedule seems to be generally well tolerated,” he added, although the combination could cause more side effects, he told Yahoo News.

According to the report, other recent studies and government Germany, Combo Excellent Preliminary studies suggest that it is less effective than the mRNA vaccine in the fight against delta and beta mutants by boosting immunity over two doses of the same drug, especially AstraZeneca.

Box containing vials of Oxford / AstraZeneca COVID-19 vaccine

Oxford / AstraZeneca COVID-19 vaccine vials are stored in the refrigerator at the London Vaccine Center. (Dinendra Haria / SOAP Images / LightRocket via Getty Images)

Dr. Soumya Swaminathan, WHO Chief Scientist, said online: Press conference Before revealing in a tweet a few hours later last week that she was referring to an individual rather than a health agency.

WHO does not widely support the mixing of different vaccines unless the first vaccine supply is available.

“For best protection, WHO recommends that both doses of the two-dose regimen be administered at recommended intervals,” said the WHO European Vaccine Preventable Disease and Immunization Program Program. The manager, Dr. Siddhartha Datta, told Yahoo News. “WHO recommends using the same product for both doses.”

Even Pfizer is wary of mixed approaches, as noted in the media office’s written response to Yahoo News. “Compatibility is not part of current regulatory approvals. [Pfizer-BioNTech] vaccine. As a biopharmacy company working in a highly regulated industry, our position is supported by labels and indications agreed with regulators and is communicated by data from Phase 3 studies, “the company said in an email. .. “Therefore, we are not currently in a position to support mixed schedules.”

However, countries that were initially heavily dependent on AstraZeneca’s adenovirus vaccine (such as Canada, where a quarter of vaccinated citizens received different types of injections) have done some recent research. I’m pointing out. 1 With Spain Another In the UK, it has shown beneficial results.

Nurse prepares dose of Pfizer-BioNTech vaccine

A nurse prepares a dose of Pfizer-BioNTech vaccine in Quito, Ecuador. (Rodrigobu Endia via Getty Images / AFP)

For López-Acuna, all vaccines, especially one-off vaccines, tend to be less effective against new variants.Recently Research According to the New England Journal of Medicine, either AstraZeneca or Pfizer’s one-shot was only 30% effective in protecting against highly contagious delta mutants. (In two doses, the Pfizer vaccine showed 88% efficacy against Delta, while AstraZeneca showed 67%.)

“We need to continue vaccination and schedule completion for those who have only one vaccine,” he said, saying that countries such as Spain, where the Delta is exploding, have social distance restrictions and nightclubs. He added that measures such as closures need to be maintained.

However, Feigl-Ding accepts at least considering the feasibility of the DPT vaccine. “I really don’t like WHO Chief Scientists [mixing vaccines] It’s like being in a world without evidence. But in a sense, there are many things in the world without evidence. As you know, there are no randomized trials for parachute wear and death prevention. It makes sense for a parachute to slow you down and prevent it. “

Richard Carpiano, a professor of public policy and sociology at the University of California, Riverside, told Yahoo News that he understands how uncertainty can be mistaken for instability.

“We expect to give scientists and clinicians a definitive answer, but that’s not how many ordinary sciences work. Only a year ago, we knew very little. As the coronavirus situation is constantly evolving, the scientific community is moving rapidly to understand it, and guidelines are updated frequently. This is in fact science is working properly. That’s it, “he said. “But for many civilians, this ongoing update risks being considered unaware of what science and public health authorities are doing.”

Robert Brass, left

Women receive Pfizer COVID-19 vaccine at a mobile clinic in East Los Angeles, California (Frederic J. Brown / AFP via Getty Images)

Also, according to Feigl-Ding, the efficacy of the combination with the J & J vaccine is unknown, and unpeer-reviewed findings suggest that it is far less effective than mRNA jab against mutants of COVID-19. doing.

For Dr. Peter Hotez, a vaccine scientist at Baylor College of Medicine, the biggest problem is complete vaccination of everyone, including people in poorer parts of the world, such as Africa, where less than 1% of the population is infected with COVID. Is to do.

“There is no perfect vaccine,” he told Yahoo News. “But I think we can vaccinate a way out of this. At some point, I think we’ll need a third immunization, but if we can vaccinate enough people, we’ll get out of this epidemic. I think we can get out of it. “


Read more from Yahoo News: