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To booster or not to booster?
Infectious disease experts weigh in on who should get a vaccine booster and whether the extra shot is a good idea for travel and family gatherings.
This fall, as my in-their-late-70s Polish mother and Romanian father prepared to make their annual pilgrimage from their adopted California back to the motherlands (a journey they skipped last year due to the pandemic), I started to get a little nervous. I was completely onboard with them reigniting their international travels once they had been fully vaccinated earlier this year. But as reports started to mount about the waning efficacy of the COVID vaccines in the face of the Delta variant and the possible need for a booster shot, especially for more vulnerable populations, the idea of them traveling abroad without the extra coat of COVID armor suddenly felt less safe than several months prior.
But my parents were determined to go. They aren’t getting any younger, for one, and they have properties that needed their attention, and friends and family they hadn’t seen in years. So, we started scrambling for information. Was it worth delaying the trip until after they received a booster? Should they just travel to Europe without a booster and get one when they returned two months later? Since they were fully vaccinated more than six months ago, could their vaccination status actually be considered “expired” or inadequate in some countries in Europe?
As countless vaccinated travelers prepare to hit the road this fall and winter, they may also wonder how a booster shot can and should factor into their trip plans.
“If you’re traveling, it’s an added layer of protection,” says Dr. William Schaffner, medical director of the National Foundation for Infectious Diseases (NFID) and a professor at Vanderbilt University School of Medicine Division of Infectious Diseases. “Travel by its necessity will undoubtedly bring you into close contact with lots of people.”
At press time, the U.S. Centers for Disease Control and Prevention (CDC) recommends a COVID-19 booster for Pfizer-BioNTech vaccine recipients who were fully vaccinated at least six months ago and are at least 65 years of age, or are 18 and older and live in long-term care or a high-risk setting, have underlying medical conditions, or work in a high-risk environment (namely healthcare and frontline workers who interact with patients, clients, students, or customers on a regular basis).
Those who aren’t yet eligible may become so soon. While Pfizer is the only vaccine that currently has U.S. Food and Drug Administration (FDA) approval for a booster shot, Moderna and Johnson & Johnson vaccines are close behind—the FDA is currently looking at the data for authorizing the Moderna and Johnson & Johnson boosters, with announcements expected in mid-October. For the time being, the CDC does not recommend “mixing and matching” vaccines, but that data is also being collected and looked at. For now, the booster should be of the same vaccine administered for the initial dose or doses, per the CDC.
Will those under 65 be advised to get a booster shot in the near future? The recommendation is “likely . . . not too far down the road,” says Dr. Schaffner. “I think we’re moving in that direction.”
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In late July, the CDC released updated guidance based on new data that had emerged regarding the now-dominant Delta variant as well as other newer coronavirus variants. The agency found that while the three FDA-authorized COVID-19 vaccines—Pfizer, Moderna, and Johnson & Johnson—remain “highly effective” at preventing hospitalization and death, their effectiveness in preventing asymptomatic and mild infection has declined in the face of newer variants when compared with the ancestral strain, which is leading to breakthrough infections among the vaccinated.
Enter: the COVID booster shot
“The group that unequivocally will benefit most from this booster from their own health point of view to minimize the likelihood of them landing in the hospital and having a bad outcome are people over 65 and [who] are immunocompromised,” says Dr. Thomas Russo, chief of infectious diseases at the University of Buffalo’s Jacobs School of Medicine and Biomedical Sciences.
Like Dr. Schaffner, Dr. Russo also believes that a booster shot will ultimately become available to the majority of adults. While the case for getting a booster is strongest for vulnerable groups, Dr. Russo notes there’s also a case to be made for others to consider the booster.
“If you get that third shot not only are you going to help that 65-and-up immunocompromised group from developing more severe disease and more bad outcomes, but you’re [also] going to, to a degree, decrease the amount of those asymptomatic or breakthrough infections as well, which could have important implications for transmissions,” says Dr. Russo.
The booster campaign, however, is not without confusion and controversy. Earlier this month, the World Health Organization (WHO) issued its latest guidance on COVID-19 vaccine boosters, emphasizing that providing boosters risks “exacerbating inequities in vaccine access” by diverting supply from vulnerable populations in some countries that are still working to administer their initial vaccine doses.
The other issue is that the main goal of the vaccination campaigns during the COVID-19 pandemic is to protect against severe illness, hospitalizations, and death, as per the WHO statement on boosters. While the efficacy of the COVID-19 vaccines wanes in the face of newer variants, the breakthrough infections are still predominantly asymptomatic, mild, or moderate COVID-19 cases, meaning that the vaccines are still very good at preventing severe illness and death.
“The majority of infections, hospitalizations, and bad outcomes are in the unvaccinated,” says Dr. Russo. “These boosters are some value added to the fully vaccinated but at the end of the day, the greatest return in investment from a public health point of view is trying to get all those unvaccinated people vaccinated.”
At press time, the CDC considers anyone who is two weeks out from having received their second of two doses of the Pfizer or Moderna vaccines or from the one-dose Johnson & Johnson vaccine to be fully vaccinated. Whether or not that will change in time in the face of future variants and as additional data is collected regarding the ongoing efficacy of the vaccines remains to be seen.
There are some signs that those initial doses won’t be enough to be considered fully vaccinated by some countries. This week, Israel became the first country to require a booster shot for citizens and residents to be considered fully vaccinated and to access the country’s COVID Green Pass, which is needed to enter indoor venues. Passes for those who have received two vaccine doses and those who have recovered from COVID-19 are valid for six months after the date of their completed vaccination or recovery.
In Croatia, international visitors are considered fully vaccinated as long as their completed vaccine certificate is no older than 365 days. OK, that’s a full year, but for those who were among the very first to get vaccinated in December 2020 and January 2021, that year is coming up quickly. Austria, too, has a cutoff: 360 days after a double-dose vaccine or 270 days after a single-dose vaccine such as Johnson & Johnson. According to Austrian authorities, COVID booster doses will “extend the validity of vaccination status for an additional 360 days starting on the day of receipt of the booster dose.”
Travelers should pay close attention to whether there is a period of validity for their vaccination status in the destination(s) they plan to visit.
There’s another factor to consider, too.
“Obviously, if you test positive at any time during your travels, that could throw a significant wrench in your travel plans,” says Dr. Russo, referring to the many COVID-19 testing requirements that are now an integral part of the international travel process. (That includes the fact that all international passengers age two and older flying into the U.S. are required to provide proof of a negative COVID-19 test procured within three days before their flight to the U.S.)
Not only does a booster enhance protection for more vulnerable travelers, but for those who want to improve their odds of having mandatory COVID-19 tests come back negative and of not having their trip derailed by a positive result, “those third shots are going to be helpful in that as well,” says Dr. Russo. “I think a booster is a great idea if you’re traveling because who doesn’t want to travel with max protection?”
Fall leisure travel is one thing; reuniting in close quarters with friends and family for the holidays is a whole other.
“It’s very possible we’ll see a spike this winter, both of COVID and other respiratory infections,” says Saskia Popescu, senior infection prevention epidemiologist at George Mason University.
As we tiptoe into the holiday season, there are several factors to consider. For one, the COVID booster is now recommended for those age 65 and older, as well as for all adults who live or work in higher risk settings. Secondly, the vaccines have yet to be approved for children under the age of 12—though Pfizer this week submitted data to the FDA for approving its vaccine for children 5 to 11 years of age with a decision expected sometime between Halloween and Thanksgiving.
Even if the vaccines get approved for children age 5 and up, many multigenerational families will be facing some decisions about how to safely address gatherings where those who cannot yet be vaccinated are mingling with the vaccinated.
There’s also the issue of those who are unvaccinated by choice. The CDC this week issued a recommendation that unvaccinated individuals delay domestic travel until they are fully vaccinated, and infectious disease experts echoed that sentiment in the context of family gatherings.
When it comes to forthcoming get-togethers, “I really encourage people to keep an eye on what’s going on in their community [with regards to transmission], try to ensure everyone is vaccinated if they’re gathering, and try to infuse some other interventions like masking or doing things outdoors,” advises Popescu.
Dr. Russo recommends laying some ground rules for the holidays:
Associated Press contributed reporting.
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