▶ Watch Video: COVID-19 vaccine hesitancy concerns, warnings about new variants

Authorized vaccines in Europe and the United States each respond to all known variants of the virus, the World Health Organization said Thursday. Scientists are still researching the rate of effectiveness and transmissibility of some existing strains of concern. 

“All COVID-19 virus variants can be controlled in the same way with public health and social measures,” European Regional Director Hans Kluge said at a press conference. “All COVID-19 virus variants that have emerged so far do respond to the available approved vaccines.” 

There are four main variants of concern that have been monitored since January 2020, Kluge said. That includes the B.1.617 mutation that currently is devastating India. B.1.617 has been detected in 44 different countries in all six WHO regions and the WHO has received reports of detections in five different countries, according to a recent weekly epidemiological update from the WHO. Multiple variants of the virus that cause COVID-19 are predicted by the Centers for Disease Control and Prevention to increase proportions throughout different regions of the world in the future.

Unknown variants of the virus could still emerge and could be resistant to current vaccine formulas, scientists at Johns Hopkins Medicine explained. Experts noted that variant B.1.351 which was first detected in South Africa might be resistant to some vaccines in development and that mutations like it are still being studied.

But early trial results showed that Moderna provided increased immunity results against variants of the virus found in South Africa and Brazil. Pfizer’s original vaccine was also shown to be highly effective against the variant which was first spotted in the United Kingdom. 

Should existing vaccines prove to be less effective against any emerging variants in the future, the WHO stated that “it will be possible to change the composition of the vaccines to protect against these variants.”

“For the time being, we can say that all the four variants do respond to the vaccines made available, as of today,” Kluge said. “But the best way to counteract is to speed up the vaccination roll out.” 

To date, 37.8% of Americans are fully vaccinated, according to the CDC. In the past week, the CDC also reported a 23.6% decrease in new daily COVID-19 cases.  

 Throughout the U.S., states have also adopted new guidance on mask mandates following a CDC update that said fully vaccinated people no longer have to wear them in many instances. 

But Kluge said that “there is no such thing as zero risk” and warned people to still remain cautious despite more vaccines being distributed. 

“Vaccines may be a light at the end of the tunnel but you cannot be blinded by that light,” Kluge said. “We have been here before. Let us not to make the same mistakes that were made this time last year that resulted in the resurgence of COVID-19.” 

He said that most cases are linked to international travel and warned people to “exercise caution and rethink or avoid international travel,” despite countries around the world reopening up to tourism. He advised adhering to social distancing protocols, wearing a face mask in public, and avoiding crowded spaces. 

“We are heading in the right direction but need to keep a watchful eye on the virus,” he said. “In the face of a continuous threat and new uncertainty, we need to continue to exercise caution.” 

On Wednesday, the European Union relaxed tourism travel for visitors and eased the criteria for nations to be considered safe countries.