Study: New booster doses against “Covid-19” provide limited protection

Dubai, United Arab Emirates (CNN) — Updated COVID-19 boosters with antibodies that fight the now circulating Omicron variant and its variants provide some protection against infection, according to the first study to look at how boosters perform in the real world. However, the researchers saw that the protection provided by these boosters is not as great as that provided by the original vaccine against previous coronavirus variants.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, called the new data “very good, actually.”

In a meeting with the media held at the White House on Tuesday, Fauci said: “Please, for your personal safety, for the sake of your families, receive the updated ‘Covid-19’ dose as soon as you become eligible for it, in order to protect yourself, your families and your community.”

Absorption of the bivalent booster doses, which protect against the BA.4/5 sub-mutants and the original virus strain, was notably slow. Only 11% of eligible Americans received the booster dose when it became available in early September.

The new study found that the updated boosters work just as well as the original ones. They protect against symptomatic disease by between 40% and 60%, which means that even when the protection provided by the vaccine is most effective, people may still be exposed to “Covid-19” about a month after receiving the vaccine.

These percentages are more or less the same as the typical efficacy of influenza vaccines. Over the past 10 years, data from the US Centers for Disease Control and Control (CDC) showed that the effectiveness of seasonal influenza vaccines ranged from 19% to as high as 52%, versus the need to see a doctor because of the flu. The effectiveness varies based on how similar the vaccine strains are to the disease-causing strains.

The authors of the new study stated that people should realize that “Covid-19” vaccines no longer provide more than 90% protection against accidental infections, as was the case when the vaccine was first introduced in 2020.

“Unfortunately, the protection rate was between 90% and 100% in the pre-Delta variant,” said Dr. Ruth Link-Gillis, an epidemiologist at the US Centers for Disease Control and Prevention. “And we saw it drop with Delta up to 70%.” It’s even lower with the ‘Omicron’ mutant, it’s close to 50%. And so I think what we’re seeing here is that the bivalent vaccine really brings you back to the kind of efficacy that we were going to see immediately after the previous boosters, which is great.” And she continued, “This is the goal that we aspire to achieve.”

Vaccines are just one of the tools for staying healthy

“It’s not 100% protection, but it’s important,” Link-Gillis said. And she continued, “Especially with the approaching holidays and the possibility of traveling, spending time with elderly relatives, and people with weak health. I believe that having some protection from disease, and thus protecting your loved ones from infection, is better than the lack of protection.”

This also means, Link-Gillis noted, that people should continue to take a layered approach to protection, using rapid testing, high-quality masks, and ventilation as a comprehensive approach, rather than relying on vaccines alone.

Link-Gillis added that she expects the vaccine’s protection against serious “Covid-19” repercussions, such as hospitalization and death, to be higher, but this data is not yet available.

The study, which was led by scientists from the US Centers for Disease Control and Control (CDC), relied on the health records of more than 360,000 tests conducted by nearly 10,000 retail pharmacies between September 14 and November 11, the period in which it caused the virus. BA.4 and BA.5 account for the most cases of COVID-19 in the United States. The study included 18-year-olds and older who tested positive for COVID-19 and were not immunocompromised.

The study looked at the effectiveness of boosters in two ways:

First, the researchers calculated a value known as absolute vaccine efficacy, which compared the odds of developing symptoms in people who received bivalent booster doses with those who reported not being vaccinated.

Second, they calculated relative vaccine efficacy, which looked at the odds of developing symptoms in people who received the updated bivalent booster doses, compared with those who received two, three, or four doses of the original, single-strain vaccine.

Compared to unvaccinated people, adults ages 18 to 49 who were given bivalent boosters were 43% less likely to contract COVID-19.

The elderly, who were more likely to have weakened immune function, received less protection. And those between the ages of 50 and 64 years, their immunity reached approximately 28%, while those aged 65 years and over were 22% less likely to be infected with the “Covid-19” virus compared to the unvaccinated group.

The relative efficacy of the vaccine showed the additional protection people might expect, in addition to the protection left by previous vaccine doses. If two to three months have passed since the last dose, bivalent boosters add, on average, 30% protection for those aged 18-49 years, over 31% protection for those aged 50-64 years, and 28% protection more if they are 65 years of age or older.

The agency’s data showed that 3 months after the last booster dose, people aged 50 and over still had about 20% protection against COVID-19. Altogether, the upgraded boosts increased their effectiveness by almost 50% against incidental injury.

More than eight months after the last dose of vaccine, a person gets protection from boosters. But Link-Gillis said that by eight months, there would be little protection left over from previous booster doses against Omicron and its variants, meaning the vaccine’s effectiveness for this group may have been close to comprehensive protection against infection.

As for those between the ages of 18 and 49 years who had received the last dose of the vaccine eight months or more, they received an additional 56% protection against infection with “Covid-19” accompanied by symptoms, while adults between the ages of 50 and 64 years enjoyed protection. an additional 48%. Also, the extra protection rate for adults over the age of 65 is 43%, in addition to everything left over from previous vaccinations.

Short and modest protection from boosters

It boils down to the fact that boosters will likely reduce your risk of disease by 50 percent, but that protection likely won’t last, said John Moore, an immunologist and microbiologist at Weill Cornell Medicine.

Moore, who was not involved in the study, said, “Getting a booster will give you some extra protection against infection in the short term, which we always see with a booster, but it won’t last long. It will wane, and it will wane even more as it spreads.” mutants with greater resistance.

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