The latest worrying variant of the coronavirus exploits low global vaccination rates and the rush to ease pandemic restrictions, adding new urgency to the push for more shots and slowing its rapid spread.
The vaccines most widely used in Western countries still appear to offer strong protection against the highly contagious delta variant, first identified in India and now spreading in more than 90 other countries.
But the World Health Organization warned this week that a trifecta of a more easily spread strain, a population not being sufficiently immunized and a decline in the use of masks and other public health measures before the virus can be better controlled will “delay the end of the pandemic.”
The delta variant is positioned to take full advantage of the cracks in any country’s armor.
“The widespread vaccination remains even more critical, because the viruses we have circulated are actually more transmissible than the original wild strains,” said Dr. Rochelle Walensky, director of the US Centers for Disease Control and Prevention.
Amid concerns about the spread of the variant, parts of Europe have reinstated travel quarantines, several Australian cities are in outbreak-triggered lockdown – and just as Japan is preparing for the Olympics, several visiting athletes have become infected. The mutation is causing concern even in countries with relatively successful immunization campaigns, but which have not yet reached enough people to quell the virus.
For example, the mutant has forced the UK, where almost half of the population is fully vaccinated, to delay for a month the lifting of the long-awaited COVID-19 restrictions, as cases double every nine days.
In the US, “we are still vulnerable to this volatility and rebound,” said Dr. Hilary Babcock of the University of Washington at St. Louis.
The variant “was able to find loopholes in our protection,” he said, pointing to how hospital beds and intensive care units in the least vaccinated southwestern state of Missouri suddenly filled up — mostly with adults under 40 who had never had the shot. . With nearly half the US population immunized, CDC tracking shows the variant spreads most rapidly in the swath of the country with the lowest rates.
But the variant poses the greatest danger in countries where vaccination is rare. Africa is seeing cases rising faster than ever, driven in part by mutations, the WHO said Thursday, while areas in Bangladesh bordering India also saw a variant-driven spike. Fiji, which went through its first year of the pandemic without just two deaths from the virus, is now experiencing a significant outbreak blamed on the strain, and Afghanistan is desperately looking for oxygen supplies for it.
The delta variant remains far from being the only version of the coronavirus to spread — and you don’t want to catch anything. Here’s what scientists know so far:
EASIER SPREADING IS THE MAIN THREAT
Scientists believe the delta variant is about 50% more contagious than the other strains. Researchers are just beginning to uncover why. But there are early clues that some mutations could facilitate a key step in how the virus gets into human cells, said Priyamvada Acharya, a structural biologist at the Duke Human Vaccine Institute.
However, it is not clear whether the higher transmission is the reason why this variant spread so quickly. In the UK, the increase followed an easing of restrictions in May, when restaurants, gyms and other businesses reopened and thousands of fans had attended sporting events.
WHAT IS MORE DANGEROUS?
It’s harder to say whether the delta variant makes people sicker. British experts said there were some early signs it could increase hospitalizations, but there was no evidence it was any more lethal.
This triggered a devastating spike in COVID-19 in India in February, and “this time we have more people who are very sick than ever before,” said Dr. Jacob John of Christian Medical College in Vellore. But he cautions that an “explosion” of cases doesn’t mean this version is more dangerous, as more cases usually means more hospitalizations.
THE BEST PROTECTION IS FULL VACCINATION
British researchers found two doses of the Pfizer-BioNTech vaccine or AstraZeneca vaccine were only slightly less effective at blocking symptomatic disease from the delta variant than from the previous mutation – and importantly, remained highly protective in preventing hospitalization.
But there’s an important catch: Just one dose has been shown to be much less effective against the delta variant than it was against previous versions of the virus. That had prompted England, who initially extended the gap between doses, to speed up the second shot.
There is little information about whether the delta variant can escape other vaccines, such as those developed in China or Russia.
Experts say Moderna’s vaccine, the same strain as Pfizer’s vaccine, should also be protective. Johnson & Johnson is still studying how its single-dose vaccine fares against the variant. The company notes that its shot does protect against a different worrying mutant – the so-called beta variant that emerged in South Africa and is still considered the biggest challenge to a current COVID-19 vaccine.
WHAT ABOUT MASK?
The WHO has urged governments not to lift pandemic restrictions too soon – including saying everyone, even those vaccinated, should continue to wear masks given that the delta variant spreads more easily and no vaccine is 100% effective.
In the US, the CDC says fully vaccinated people can go mask-free. But there is no way of knowing whether people without masks are actually vaccinated and local governments can set stricter guidelines. This week, with the delta variant spreading locally, health officials in Los Angeles County said they are still recommending masks indoors in public places for everyone.
If that’s confusing, consider that the more the virus spreads in a given area, the greater the risk that even the vaccinated will get a mild or asymptomatic infection that could spread to someone unprotected – such as children who are too young to qualify for the shot.
In Missouri, a fully vaccinated Babcock ensures he has a mask to wear quickly if he encounters a crowd: “I feel like the new normal I have the mask in my hand, ready to put it on if I need it.”