Three new studies from the US Centers for Disease Control and Prevention (CDC) highlight the importance of getting the booster dose of the vaccine to provide the best protection against Omicron.
This is the first real-life data to examine effect enhancers against the Omicron variant of Covid-19, which now accounts for more than 99% of coronavirus cases in the country.
The studies, released this Friday (21), raise the question of whether people with just two doses of vaccine should still be considered fully vaccinated.
“I think we have to redefine ‘fully vaccinated’ those with three doses,” said William Schaffner, a longtime CDC vaccine consultant who was not involved in the studies.
The studies are huge in scope, involving millions of cases, thousands of visits to emergency departments and urgent care centers, and tens of thousands of hospitalizations among adults.
The booster was 90% effective at preventing hospitalizations during a period between December and January, when Omicron was the dominant variant, according to a CDC study that analyzed nearly 88,000 hospitalizations in 10 states. In comparison, getting two doses was 57% effective in the period after at least six months of the second injection.
The extra vaccine was 82% effective in preventing visits to emergency rooms and urgent care centers, according to the study, which analyzed more than 200,000 visits in 10 states. In comparison, receiving two doses was only 38% effective in preventing these visits when at least six months had passed since the second injection.
“I think it’s the third dose that really gives you the strongest protection,” Schaffner said.
That study was published Friday in the CDC’s Morbidity and Mortality Weekly Report (MMWR).
A second study, also published in MMWR, concluded that people with three doses were less likely to be infected with Ômicron.
Analyzing data from 25 state and local health departments, CDC researchers found that among those who received boosters, there were 149 cases per 100,000 people, on average, each week. For those who took just two doses, it was 255 cases per 100,000 people.
A third study, published in the scientific journal JAMA, showed that having a booster shot helped keep people from getting sick with Ômicron.
That study looked at just over 13,000 cases of the variant in the US and found that the odds of developing a symptomatic infection were 66% lower for people who received a booster compared to those who received just two injections.
All three studies found that unvaccinated people faced the greatest risks of becoming seriously ill with Covid-19.
The CDC says a person is considered fully vaccinated when they receive their primary Covid-19 vaccines — two weeks after receiving the second dose of an mRNA vaccine or two weeks after the first dose of the Johnson & Johnson vaccine.
Booster shots are recommended for everyone aged 12 and over.
Less than half of those eligible to receive booster shots have received one, and only about 25% of the total US population is fully vaccinated and boosted, according to CDC data.
Nearly 20% of the US population eligible to be vaccinated have not yet received any doses of the cornavirus vaccine.
This content was originally created in English.
original version
Reference: CNN Brasil
