²ÝÁñÉçÇø

Pfizer/BioNTech and Moderna, makers of currently the only U.S.-approved COVID-19 vaccines, are both developing booster shots to improve protection against troubling new strains of the virus.

The development of Pfizer/BioNTech boosters against variants that could have resistance to current vaccines was announced on Tuesday, according to Reuters. On Monday, Moderna revealed that it was  to better protect against the South African B.1.351 virus strain, which is believed to be significantly more contagious than versions of the virus that are frequently seen in U.S. patients.

Pfizer told Reuters that the company was "already laying the groundwork to respond quickly if a variant of SARS-CoV-2 shows evidence of escaping immunity by our vaccine."