According to a study by France’s Pasteur Institute, Pfizer’s COVID-19 vaccine is slightly less effective but appears to still protect against the more transmissible variant of the virus first identified in India, The Japan Times reported.

Olivier Schwartz, the institute’s director and co-author of the study that was published on the BioRxiv website, remarked that “despite slightly diminished efficacy, the Pfizer vaccine probably protects” against the Indian variant, according to laboratory test results.

The study sampled 28 healthcare workers in the city of Orleans. Sixteen of the participants received two doses of Pfizer’s vaccine, while 12 received one dose of AstraZeneca’s vaccine.

The study found that people who had received two doses of the Pfizer vaccine saw a threefold reduction in their antibodies against the Indian variant but were still protected.

“The situation was different with the AstraZeneca vaccine, which induced particularly low levels of antibodies neutralizing” the Indian variant, according to the study.

Patients who had COVID-19 within the past year and people vaccinated with two doses of Pfizer retained enough antibodies to be protected against the Indian variant, but three to six times less antibodies than against the UK variant, Schwartz said.