5 things travelers need to know about the delta COVID-19 variant

Last week, the World Health Organization (WHO) warned that even fully vaccinated individuals — those who received their final dose of the COVID-19 vaccine at least two weeks prior — should still wear a mask as the delta variant spreads.

This differs from current guidance from the U.S. Centers for Disease Control and Prevention (CDC), which relaxed indoor mask-wearing guidance for fully vaccinated people this spring.

But the warning comes as the delta variant strain of the coronavirus continues to spread worldwide. The delta variant, first discovered in India, is quickly becoming the world's dominant strain and has been traced to an outbreak of fully vaccinated adults in Israel, prompting that country to require people to wear masks again.

To find out more about the delta variant and what it could mean for your travel plans, TPG spoke with Dr. Jenny Yu, the senior manager of medical integrity at Healthline Media (which is owned by TPG's parent company, Red Ventures), through email.

This interview has been edited for clarity.

Should people rethink their summer travel plans?

Dr. Jenny Yu: People should weigh these factors while traveling for the summer: vaccination status, health risks and local regulations. If you are vaccinated and continue to wear a mask, the risk of contracting the virus remains fairly low.

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For families with children who are not vaccinated, mask-wearing is good protection. In addition, it's good to know where the hotspots of the delta variant are, and the local regulations of testing and quarantine for both vaccinated and nonvaccinated individuals so that there are no surprises to ruin travel plans.

Does my vaccine protect against this variant? Will I need a booster shot?

Dr. Yu: Data has shown that the [two-shot] mRNA vaccines (Pfizer and Moderna) are 88% effective in protecting against the delta variant. A recent study out of Washington University suggests there could be sustained protection against the virus. When and if we will need a booster is still to be determined.

How effective are the different vaccines against the delta variant?

Dr. Yu: The mRNA vaccines (Pfizer and Moderna) are 88% effective after the two shots. The Astra-Zeneca/Oxford vaccine is 60% effective after the two shots. More data is needed for whether recipients of the Johnson & Johnson vaccine will need a second booster.

What are the concerns about the delta variant? Is it more contagious or severe?

Dr. Yu: The Ddelta variant is the more contagious of the variants. It can produce mild symptoms in even vaccinated individuals. It is most dangerous to unvaccinated individuals as they are likely to contract the virus.

What regions are currently experiencing outbreaks of the delta variant?

Dr. Yu: In the U.S., the Southeast and the Midwest have higher concentrations of the delta variant, with Missouri having the highest documented cases. Worldwide, the United Kingdom, South Africa, South America (Brazil) and Australia are seeing accelerated cases of the delta variant.