Moderna says COVID-19 vaccine performed well in a lab against delta variant

Moderna’s COVID-19 vaccine performed well in a lab setting against variants of the virus, including the rapidly spreading and highly contagious delta variant first found in India, the company announced Tuesday.

The mRNA vaccine produced neutralizing antibodies after two doses against delta as well as the beta and eta variants first found in South Africa and Nigeria, respectively, according to Moderna.

The vaccine did not perform as well against certain versions of the South African beta variant relative to the ancestral strain.

The data, which has not been peer reviewed, used serum samples from eight participants obtained one week after participants’ second dose of the company’s primary COVID-19 vaccine. However, the results came from lab testing and may not reflect how effective the vaccine performs in the real world.

“As we seek to defeat the pandemic, it is imperative that we are proactive as the virus evolves. These new data are encouraging and reinforce our belief that the Moderna COVID-19 vaccine should remain protective against newly detected variants,” Moderna CEO Stéphane Bancel said in a statement. 

The announcement comes on the same day Moderna said its vaccine had been granted emergency use authorization in India, where the delta variant is thought to have fueled a massive outbreak.

The variant is spreading rapidly. It makes up about 20 percent of U.S. cases, and is expected to become the dominant strain worldwide. Evidence points to all available vaccines in the U.S. being effective against the delta variant, but the threat is serious to people who are not vaccinated.

The World Health Organization last week urged caution and recommended everyone, even the fully vaccinated, to continue to wear masks, keep physically distant and avoid crowds. 

“Vaccine alone won’t stop community transmission,” said Mariangela Simao, WHO assistant director-general for access to medicines and health products, referring to areas of the world like Latin America with continuously high levels of community transmission. 

“People need to continue to use masks consistently, be in ventilated spaces, hand hygiene … the physical distance, avoid crowding. This still continues to be extremely important, even if you’re vaccinated, when you have a community transmission ongoing,” Simao said.

U.S. officials and the Centers for Disease Control and Prevention, however, have said fully vaccinated people do not need masks and do not need to worry about the delta variant.

Access issues, vaccine hesitancy, and outright refusal remain major barriers in the U.S., but it’s not realistic that leaders will broadly re-impose mask mandates and distancing requirements. Experts predict localized surges in areas of low vaccination, and are urging everyone to get vaccinated as quickly as possible.