Have Covid jab, will travel — but is it as simple as that?

Vaccines are rolling out, slowly but surely, across the world. Does that mean it’s time to think about travelling yet?

The tourism industry would like to say yes. According to the most recent data from the World Travel and Tourism Council, published in early November, the restrictions on travel caused by the coronavirus pandemic were projected to take $4.7-trillion out of global GDP in 2020 alone.

But medical professionals still urge caution, a message that will remain imperative, even after individuals have been vaccinated against Covid-19.

Among their warnings: vaccines are not 100% effective; it takes weeks to build up immunity (after the second shot); little is known about the ability to transmit Covid-19, even after immunisation; and herd immunity will be a long way off. Their consensus is that risks will remain, but freedom of movement can safely increase — allowing for at least certain types of trips — among individuals with protection against the virus.

Yes, you will still need to wear a mask. 

Here’s what else you’ll need to know about travel safety in the months ahead, whether you’ve already got your shot or are looking for normalcy somewhere on the horizon.

What we know and what we don’t

The Covid-19 vaccines approved to date, both in the US and Europe, have proven to be exceptionally safe, effective, and the strongest tool yet in combating the pandemic. Still, there are known unknowns, particularly when it comes to possible virus transmission after vaccination.

This question boils down to one point: clinical trials for the now approved vaccines, including those from Pfizer and Moderna, did not include regular polymerase chain reaction (PCR) testing of the study participants. Without any data about their ability to carry the virus, there’s enough conclusive evidence only to suggest that vaccines result in 95% effective protection from symptomatic infection, says Dr Kristin Englund, infectious diseases specialist at the Cleveland Clinic.   

“For the most part, if you’re vaccinated against [a disease] — say chickenpox or measles, you should not be able to transmit that virus to someone else,” explains Englund, adding that there’s no known reason to believe that Covid-19, or its related vaccines, should behave differently. “I anticipate that’s what we’ll see [with Covid-19 vaccines as well], but we have to wait until studies prove it before we can lower our guard substantially.”

There are other important unknowns, too. “To see a vaccine that is 95% effective, those are remarkable numbers, much better than we ever anticipated,” says Englund. “But we don’t have the ability right now to know who will have a good response [to the vaccine] and who will be one of the 5%.”

How to think about herd immunity

Another unknown, to a lesser extent, is what it will take to achieve herd immunity.

“The general consensus is that it will take somewhere between 70% and 80% [of the population being immune] to eliminate widespread risk, maybe more,” says Dr Scott Weisenberg, who serves as both director of the infectious disease fellowship programme at New York University and as medical director of the university’s travel medicine programme. “We’re many months away from that, assuming that the vaccine actually does remove transmission and that people get it.”

In a best-case scenario where everything goes right, Weisenberg believes herd immunity can be achieved in the US sometime this summer, pending the approval of easier-to-distribute vaccines such as the one by AstraZeneca, which could speed up rollout.

That’s highly unlikely, though.

“Acceptance of the vaccine is a big, key question,” he adds. To his point, the World Health Organisation called vaccine hesitancy as one of the top 10 threats to public health in 2019, even before Covid-19 became part of the picture.

But herd immunity can be sliced and diced in many ways.

“You can talk about herd immunity within a state, within a smaller community, or even within a family,” Englund adds. “So if everyone in a room is vaccinated but one, you should be able to offer more protection to that person.”

That’s a notable consideration for family gatherings whose younger members may take longer to qualify for the vaccine than older or more at-risk members. (The approved vaccines have not yet been tested or approved for children by the US Food and Drug Administration, which may stymie air travel among multigenerational groups well into 2021.)

Deciding where to go on your next holiday — and who to travel with — may have more to do with antibodies than such normal considerations as weather and price.

“Definitely look at the current infection rate in that area and absolutely, the vaccination uptake in that population, those are two very important things,” says Englund.

Don’t be surprised if it feels like a counterintuitive exercise, adds Weisenberg.

For instance, in New York City, where 25% of the population is believed to have already contracted Covid-19, herd immunity may require a proportionately smaller number of vaccinations to achieve if the previously infected people retain equivalent antibodies.

“The risk [of picking up or spreading the virus] might actually be relatively low,” says Weisenberg about visiting Manhattan, given the strictness of lockdown measures, the historic acceptance of vaccines in urban areas compared to rural ones, and the high rates of Covid-19 testing among the local population, despite the incredible population density.

Go to Kenya, where you may have a perfectly socially distant safari, he adds, and you may have to pass through places such as Nairobi, where testing is low, and it’s hard to get an accurate picture of real-time risk.

The evolving definition of safe travel

Expect the definition of safe travel to shift week by week, especially while parts of the world bat down the surge of cases connected to holiday travel and new variants of the virus.

“You have to factor in the issues of going someplace and bringing the virus back to an area where that is consequential,” says Weisenberg. He hopes the US Centers for Disease Control and Prevention will eventually have tiered alerts for destinations, depending on local risk, in the vein of the agency’s measles alerts, but says: “It’s just too widespread right now to isolate that way.”

A good idea might be to look up hospital (and specifically ICU-bed) availability figures before committing to a holiday anywhere, to ensure the local system is not already overwhelmed.

Weisenberg also believes that the increasing accuracy of rapid Covid-19 antigen tests will help ensure safety as mobility picks up; it’s noteworthy that the new US requirements for entry include negative test results, even for those who have already been vaccinated.

“I’m going to be getting on a plane, I’ll be honest with you,” says Englund. “I’ll wear a mask, I’ll make sure we have seats where we’re not seated next to someone else, with appropriate space in between, using all of the hand sanitiser.

“We’ll get an Airbnb and spend quality time on a beach,” she says, “and if we visit local sites, we’ll pretend we hadn’t been vaccinated, approaching things with the same precautions as we would have pre-vaccine. I don’t think there’s anything wrong with that.”

Bloomberg