(HealthDay): As the number of people fully immunized against COVID-19 increases by hundreds of millions, immunologists and infectious disease experts are now asking a new question about the pandemic that is unfolding.
That is, how long it will take vaccine will immunity last and will people who have received the sting need reinforcing shots to maintain their protection?
It is an important issue, as decreased immunity to more potent variants of COVID-19 could cause future infection growths and, in the worst cases, a full return of quarantines and closures, according to experts.
A person’s immunity always decreases to some extent after vaccination or natural infection, said Dr. Greg Poland, director of the vaccine research group at the Mayo Clinic in Rochester, Minn.
But will your immunity to COVID fade away quickly, as it does with the common flu or cold, or will it last longer as it happens in diseases like measles or whooping cough?
“Antibody levels decrease over time. This is true for every vaccine we make,” Poland said. “We had never been immunized against coronaviruses, so this question is really open.”
People’s immunity to seasonal coronaviruses (those that cause the common cold) fades quickly. That’s why you can catch a cold over and over again.
But vaccines developed against the SARS-CoV-2 virus, which causes COVID, appear to create high levels of antibodies that protect even as they decline.
In a recent study of 3,900 health workers tested weekly COVID, about 5% tested positive between December and April, Poland said. But of 204 who fell ill, only 16 had been fully vaccinated against COVID-19.
“He’s talking about a 0.3% rate” of infection in fully immunized people, Poland said. “And if they were vaccinated and had advanced infections, they had 40% to 50% lower viral loads and had almost 60% less fever. If they were sick enough to be in bed, they would spend two days less in bed than the unvaccinated. “.
And this is the main factor in deciding whether boosters will ever be needed: Are vaccines successful in their most important job?
“The goal of this vaccine is to keep you out of the hospital, the ICU, and the morgue,” said Dr. Paul Offit, director of the Vaccine Education Center at Philadelphia Children’s Hospital and US Food and Drug Administration Advisor.
According to this measure, experts such as Poland and Offit now believe that boosters are unlikely to be needed soon for most or perhaps all who have been vaccinated.
Even in the face of newer and infectious variants such as the Delta variant that emerged in India, existing vaccines have been able to prevent serious diseases among fully vaccinated people, Poland said.
Offit made a similar point.
“It’s much easier to prevent serious critical illness and I think you’re much more likely to have more lasting protection against serious critical illness,” he said. “If that’s the goal, I’d imagine vaccines would last for years.”
If this type of durable protection is demonstrated, you may get COVID sniffles, but it won’t land you in the emergency room.
“When you are given a vaccine and you are not wearing a mask, the virus still enters your nose and throat. It is still starting to reproduce. It may cause some symptoms before immune system it activates, ”Offit said.
Experts who monitor hospitalization rates for COVID take into account two factors when assessing whether reinforcements are needed: the health of each person’s immune system and the development of new coronavirus variants.
People with compromised immune systems (smokers, diabetics, obese and the elderly) may need booster shots sooner if statistics show they land in the hospital at an increasing rate, Poland said.
On the other hand, younger people with healthy immune systems could have protection that lasts for years and years.
It’s just too early to tell, experts say.
“Once you see a significant number of people who have been completely vaccinated and develop serious enough illnesses to make them hospitalized, it would certainly be a sign that they will need boosters,” said Dr. Dial Hewlett, chief medical officer of disease control at the Westchester County Department of Health in White Plains, New York
Dr. Anthony Fauci, the federal government’s leading infectious disease expert, has said the protection would not be endless.
“I imagine we will need, at some point, reinforcement,” he recently told a U.S. Senate subcommittee. “What we’re finding out right now is what that interval will be.”
The main fear now is that a new variant will appear that is “different enough from the wild-type virus so that you are not protected and yet close enough that your body thinks it is what has already been seen and allows you to become infected.” you out of control “. He said Poland.
That’s why public health experts are pushing for so many people to get vaccinated as quickly as possible. The United States has just passed halfway, with more than 50% of people 12 years of age or older completely vaccinated against COVID-19, according to the U.S. Centers for Disease Control and Prevention.
President Joe Biden’s goal is for 70% of the nation to have at least one shot by July 4th. But the rate of new vaccinations has dropped recently and is now below 600,000 a day.
“The phase we are in right now is a desperate race between the vaccine and the variant,” Poland said. “If we can immunize everyone very quickly and not allow the Delta variant to gain strength, I think we will be free at home.”
Poland pointed to an encouraging model.
“There is a model that shows that if we get vaccine coverage at 50% of the entire population, we will prevent about 6 million additional cases of COVID,” he said. “This is really important, because if the virus can’t be infected, it can’t replicate. If it can’t replicate, it can’t mutate.”
The question of booster vaccines could become debatable if, as some pharmaceutical companies are investigating, the COVID vaccine will end up included in the annual flu vaccine as two by one, Poland said.
“Well, we need to get an annual flu shot. What if we wrap them up? So you may not need the coronavirus component, but we’ll increase immunity anyway as you get the flu shot.” “He said.
The U.S. Centers for Disease Control and Prevention (CDC) has more information Vaccines against covid-19.
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Citation: Will you really need an annual COVID booster vaccine? (2021, June 11), retrieved June 11, 2021 from https://medicalxpress.com/news/2021-06-people-yearly-covid-booster-vaccine.html
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