With the delta variant driving a new surge of cases, including a rising number of breakthrough cases for fully vaccinated people, attention has turned to the need for another COVID-19 vaccine dose.
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New data suggests that while the current vaccines have so far proven effective against COVID-19, the protection they offer may fade after a while.
Using that data, the U.S. Department of Health and Human Services (HHS), the CDC, the FDA and other experts in the medical field and federal government announced plans to distribute a third dose of the COVID-19 vaccine this fall. In a joint statement, the group said, “We conclude that a booster shot will be needed to maximize vaccine-induced protection and prolong its durability.”
To better understand what data experts are seeing and why it points to a need for a third dose of the vaccine, we talked to digestive disease expert and Lerner Research Institute Chair, Thaddeus Stappenbeck, MD, PhD.
Why do I need a third dose?
New research indicates that the protection the two mRNA vaccines – Pfizer and Moderna – create against COVID-19 might fade after several months. The data comes from a study of vaccinated patients in Israel, where the Pfizer vaccine was the predominant option and vaccinations began in December 2020, ahead of many other countries, including the United States.
According to the study, as the delta variant spread through Israel in the early summer of 2021, there was a correlation between receiving the vaccine at an earlier date and contracting a breakthrough case. For example, patients vaccinated in January 2021 were 2.26 times more likely to contract a breakthrough infection than those vaccinated in April 2021.
“The trials for the mRNA vaccines showed us they were up to 94% effective in protecting patients from infection,” says Dr. Stappenbeck. “But because of the situation, the other main point of those trials was to establish safety so we could start vaccinating people. We’re still learning how long that protection lasts and based on what we’ve seen in Israel, it starts to fade around six months for some people.”
He adds that the data hasn’t been investigated deeply enough yet to see if there’s evidence of why the immunity level of some people may drop. “What’s clear, though, is that more people are being exposed to the delta variant, and more people that are vaccinated are getting breakthrough infections than the initial data suggested,” he says.
“We need more studies and more data to confirm these findings,” he continues, “but, right now, the data seems to be showing us this correlation is possible.”
How do I know if my immunity is fading?
The unfortunate thing is that there’s no easy way to measure if your immunity to COVID-19 is fading, particularly if you’re a healthy adult, says Dr. Stappenbeck. “Immunity is a multi-factor thing that’s not just about the number of antibodies to a specific virus that you have in your bloodstream,” he notes. “There’s a cellular-based immunity, too, and that’s harder to measure.”
The biggest challenge for experts is that COVID-19 is a new virus — one that continues to evolve, mutate and force doctors and researchers to adapt on the fly. “It’s a moving target,” Dr. Stappenbeck says. “New data is coming out every day and we have to really watch this over the next several weeks and months.”
It’s important to note that the Pfizer and Moderna vaccines are incredibly effective against the delta variant. But a third dose would further strengthen immunity against the virus and Pfizer shared data with the FDA on this point, saying, “The data we’ve seen to date suggests a third dose of the vaccine elicits antibody levels that significantly exceed those seen after the two-dose primary schedule.”
What about the Johnson & Johnson vaccine?
So far, data related to a potential third dose is focused on the mRNA vaccines as opposed to the single-dose Johnson & Johnson vaccine. In their joint statement regarding additional doses, though, the HHS, CDC and FDA said that those who received the Johnson & Johnson vaccine will also likely need an extra dose eventually.
The experts say in their statement, “Administration of the J&J vaccine did not begin in the U.S. until March 2021, and we expect more data on J&J in the next few weeks. With those data in hand, we will keep the public informed with a timely plan for J&J booster shots as well.”
If you received the Johnson & Johnson vaccine, there’s no reason for additional concern, says Dr. Stappenbeck. “What really matters is real-world exposure,” he says, “and while Pfizer and Moderna were shown to be slightly more effective than the Johnson & Johnson vaccine in those early trials, the Johnson & Johnson vaccine is still effective against all variants thus far of COVID-19.”
Who is eligible for the third dose?
- Patients receiving active cancer treatments.
- Organ transplant patients.
- Recent stem cell transplant patients.
- Patients with advanced or untreated HIV infection.
- Patients with moderate or severe immunodeficiency.
- Patients being treated with medication that suppresses the immune system.
With more data coming in every day, federal officials are working with the CDC and FDA to establish a schedule that would deliver boosters to people 8 months after their second dose starting in late September.
When can I get my third dose?
As of right now, says Dr. Stappenbeck, there is no official guidance on getting a third dose unless you’re an immunocompromised patient. He points to the expert statement which outlines a rollout similar to what we saw with the original doses — with priority going to older, at-risk patients and healthcare workers beginning in late September.
“We’re watching this develop and waiting for those guidelines but, if you’re healthy and vaccinated, I wouldn’t panic about getting a third dose right now,” he adds.
What should I do while I wait for my third dose?
The best thing to do, says Dr. Stappenbeck, is to continue practicing social distancing guidelines, including wearing masks, six-foot distancing and maintaining good hand hygiene. This is especially true if it’s been more than six months since you’ve become fully vaccinated.
“Again, that doesn’t mean your protection has weakened since it varies from person to person,” he says. “We know that protection lasts at least six months, maybe longer. These are very unique circumstances and we’re still learning everything we can.”
In the meantime, he says, continue to be safe, and if you’re not already, get vaccinated now. “All of the real-world data suggests the vaccines are effective against the delta variant and it’s the best protection you have.”