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Vaccine efficacy – Does the Moderna syringe have an advantage over the Pfizer syringe?

New research concludes that Moderna’s vaccine may provide longer-lasting protection than Pfizer’s vaccine, as governments and scientists debate the question of who needs a booster shot and when.
Recent studies show that the injection of Moderna’s vaccine stimulates a stronger immune response than the competing mRNA vaccine from Biontech/Pfizer, and that its effects diminish more slowly.
Paul Burton, Moderna’s chief medical officer, said a series of “extremely reassuring” studies in the past few weeks showed that Moderna’s vaccine has “long-term” efficacy, that it has withstood the mutated delta and could even help people who are weakened. in the immune system.
Research published last week in the Journal of the American Medical Association found that Belgian health care workers who received the Moderna shot had more than twice the number of antibodies two months after receiving the second dose, compared to those who received the Pfizer vaccine.
According to Deborah Stencils, who co-authored the study, high antibody levels immediately after vaccination should lead to long-term protection and greater resistance to the Covid virus mutants. Although the scientists were only able to count all antibodies and not neutralizing antibodies, which is the gold standard, she said the relationship was strong enough to support the theory.
“Efficacy to protect people from severe illness and death is high in all vaccines, and this is the main goal of vaccines,” she said. “But our hypothesis is that in order for protection from mild disease to last longer, you need a higher titer of antibodies after vaccination.”
Another study last week, from the University of Virginia, found that recipients of the Moderna vaccine had more antibodies than those who received the Pfizer vaccine, with a more marked difference between the elderly. These findings mirror the findings of a draft paper last month by University of Toronto researchers assessing immune responses in long-term residents of care facilities.
Some scientists believe that Moderna’s injection could last longer because its dose of messenger RNA — the genetic code that teaches the immune system how to recognize the protein bump of the coronavirus — is three times higher than Pfizer’s. Another factor may be the time between doses, which is the four weeks recommended for the Moderna vaccine but three weeks for the Pfizer vaccine.
Eric Topol, director of Scripps Research Research Institute, said Covid vaccines appear to be more effective in countries that have maintained longer intervals between vaccine doses – such as the United Kingdom and Canada – than in the United States and Israel, which have stuck to the schedule of Phase 3 vaccine trials. He added, “I think that the rush to complete the experiments (…) confirmed the decline.”
Pfizer said its vaccine remains “highly effective”, including tackling mutant mutants, preventing further disease outbreaks and hospitalization.
The antibody studies are in addition to other “unpublished” research – pending comparison with peer studies – showing higher numbers of infections among people vaccinated with the Pfizer vaccine than in Moderna.
Research by the Mayo Clinic in the United States and Qatar has shown a better efficacy rate for the Moderna vaccine, although the results are complicated by the fact that the Pfizer injection was dispensed earlier, so it might have more time to fade, or was given to people at high risk of contracting the virus. .
These studies show a sharp decrease in potency with the appearance of the delta mutant. But previous research that followed the phase III trials showed a similar pattern: Pfizer’s effectiveness fell to an average of 80 percent against symptomatic infections after four to six months, compared to 93 percent for Moderna after five to six months.
Other vaccines may also have a longer life span than Pfizer’s vaccines. Two studies indicate that the efficacy of the Oxford/AstraZeneca vaccine is declining more slowly than the Pfizer vaccine, albeit from a lower initial rate.
Researchers from Oxford University, who are not associated with the university’s vaccine development and using data from the UK Office of National Statistics, found that the effectiveness of Pfizer’s injection against symptomatic infection was nearly halved within four months, while AstraZeneca’s protection decreased much more slowly.
This pattern is supported by data published last week from the symptom study app Zoe. The effectiveness of Pfizer fell 14 percentage points to 74 percent in five to six months, while that of AstraZeneca fell 10 percentage points to 67 percent after four or five months.
Scientists say the reason may be because the adenovirus that transmits the Oxford vaccine lasts longer in the body than messenger RNA, giving the immune system more time to respond.
Johnson & Johnson, which also uses an adenovirus, said that neutralization of antibodies in people given a single injection was actually higher eight months after vaccination than it was 29 days after vaccination.
Tim Spector, co-founder of the Zoe app and a professor at King’s College London, said: “We thought Pfizer was a matter of pride but his ability could wear off a little faster.” But he cautioned that we don’t yet have compelling evidence to distinguish between vaccines — not until significant data comes in the next six months.
Paul Hunter, an infectious disease expert at the University of East Anglia, cautioned against over-reliance on studies that could be “random bangs”. “This kind of unexpected outcome appears regularly in epidemiology,” he said.
All studies use what is called “real-world evidence”, which is collected outside the conditions of the experiment. According to John Moore, a virologist at Cornell University, the main question is whether a comparison can be made between the population receiving each vaccine, because there are local factors that can confound the results.
He said, “Is it a real comparison between similar things, or is there one or more intruders to spoil the case?” “Nothing we’ve seen so far means any difference in the mRNA vaccine booster policy,” he added.
Investors have yet to price the spreads between vaccines in an unusual market, where politicians are keeping the strings on, while doses are still in short supply.
Moderna and Pfizer’s plans for booster doses are still progressing at a steady pace, as the two companies are developing vaccines designed specifically for the delta mutant, if needed, and they are also continuing to provide data on the third dose to the US Food and Drug Administration.
The third injection boosts antibody levels. Pfizer said that people who took a booster dose at least six months after the second dose had five to 10 times more antibodies than the first two doses. Moderna presented its data on Wednesday, saying that half an extra dose of its vaccine, which still contains more messenger RNA than Pfizer’s vaccine, resulted in antibody levels “significantly higher” than what was found in the initial trial and withstood the mutant. Including mutated delta.
A vaccine that needs to be given more often could be a boon for investors, as it provides a regular revenue stream — a potential conflict of interest that has some scientists wary of the company’s initial campaign for boosters.
Topol of Scripps Research Translational Institute said he found Pfizer’s initial booster campaign “really strange”, as there seemed to be no evidence of the need for the extra shot, which could bring the company “billions of dollars”. But now, with more data coming in from Israel, Topol believes it will be needed at least for those over the age of 60.
According to Joe Walton, an analyst at Credit Suisse, it is too early to conclude any significant differences in efficacy between Covid-19 vaccines and certainly too early to have any market implications.
She believes that governments are trying to secure as many doses as possible in the short term to reconcile booster injection campaigns, potential child vaccination programs, and the risk of mutating the virus.
“Governments had no choice,” she said. “They had to have everything they could get with a rational view of supply.”
John Miller, an analyst at Evercore, said the differences in vaccines had not been “convincingly proven” and that the “horse race” between Moderna, Pfizer and AstraZeneca had not raised their stock price.
Instead, Miller said investors are concerned about whether the decline in efficacy could lead to calls for shutdowns as the delta mutant spreads and infection numbers soar: “People are more concerned about the overall viability of vaccines.”