Booster Shot: Pfizer just announced that it sees waning immunity from its covid vaccine and will be developing a booster dose that will protect people from variants. Not surprising because antibodies naturally wane over time, so studies are underway to tell if and when boosters might be needed. The initial hope with the covid vaccine was to reach herd immunity so that this pandemic would go away.
Pfizer Says They Are Making A Booster Shot
Currently, only about 48% of the US population is fully vaccinated. That’s nowhere near the threshold of herd immunity, which is estimated to be around 80%. And the hope was that with herd immunity, we could minimize the possibility of more dangerous variants developing, like the delta variant. But now we are reaching the point where different, more concerning variants pop up in the unvaccinated. And because too many people remain unvaccinated, we’re now facing the likelihood that the original vaccines are not enough to combat these new strains. And so…here come the boosters. Pfizer will seek emergency use authorization from the FDA for a booster dose in August once they release more data about how well it works.
Pfizer said quote: “As seen in real-world data released from the Israel Ministry of Health, vaccine efficacy in preventing both infection and symptomatic disease has declined six months post-vaccination, although efficacy in preventing serious illnesses remains high. These findings are consistent with an ongoing analysis from the Companies’ Phase 3 study.” So they believe that a third dose may be beneficial within 6 to 12 months following the second dose to maintain the highest level of protection.
What about the delta variant? Also known as B.1.617.2.
The delta variant is 60% more transmissible and more likely to land people in the hospital?
A few weeks ago, the Pfizer vaccine was studied in the UK regarding its impact on the delta variant. After both doses, people had 96% protection against hospitalization, and it was 88% effective against symptomatic infection. That was similar to what Canadian researchers found.
But then, just this week, a report from Israel suggests protection against MILD delta infection dropped to 64%. Pfizer said its covid vaccine booster dose produces levels of neutralizing antibodies, meaning protective antibodies, 5 to 10 times higher than what’s produced after two doses. Soon, probably in a few weeks, we’ll have published data in a peer-reviewed journal that we can comb through.
Also, Pfizer is working on a new formulation for a booster dose that may better protect against the new covid variants popping up, including the Delta, the Lamba, the Epsilon, and so on. With these new variants, what makes them more dangerous is their adaptations in the spike protein, which allows them to not only be a better key and lock fit with the ACE2 receptor but also allows them to turn the deadbolt better, if you will, to make its entry into the cell even easier.
So the new Pfizer Booster doses will serve to create antibodies in your immune system that specifically target those new mutations on that spike protein. But keep in mind that FDA EUA would be just a first step in the process. Public health authorities will still have to decide if they’re really needed.
And what about Moderna?
So far, there is no specific data available. Still, company officials say that studies have shown that the vaccine produced “promising protection in a lab setting” against the variant and others currently circulating. Since Moderna is an mRNA vaccine-like Pfizer, the expectation is that there is similar efficacy there. And so it’s also not surprising that Moderna is planning on a booster shot too. And Johnson and Johnson’s vaccine looks to remain effective against delta variant as well, at 85% efficacy.
Doctor Mike Hansen, MD
Internal Medicine | Pulmonary Disease | Critical Care Medicine
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