(WJW)– A South African researcher says the omicron variant reduces protection from Pfizer’s COVID-19 vaccine.

Alex Sigal with the Africa Health Research Institute said his team finished its first study on the effectiveness of the company’s vaccine on the latest variant, which was named following a number of positive cases in areas of South Africa.

“There is a very large drop in neutralization of omicron by BNT162b2 (the BioNTech/Pfizer vaccine) immunity relative to ancestral virus,” said Alex Sigal with the Africa Health Research Institute, in a series of tweets on Tuesday. “This was better than I expected of omicron. The fact that it still needs the ACE2 receptor and that escape is incomplete means its a tractable problem with the tools we got.”

CNBC reported the study involved blood samples from 12 people. It has not been peer-reviewed.

The makers of the Pfizer-BioNTech COVID-19 vaccine said in a press release Wednesday results from an initial laboratory study indicate the shot neutralizes the Omicron variant after three doses.

“Although two doses of the vaccine may still offer protection against severe disease caused by the Omicron strain, it’s clear from these preliminary data that protection is improved with a third dose of our vaccine,” said Albert Bourla, Pfizer chairman and CEO. “Ensuring as many people as possible are fully vaccinated with the first two-dose series and a booster remains the best course of action to prevent the spread of COVID-19.”

The World Health Organization, and even officials with the Ohio Department of Health, said it is unknown if omicron is more transmissible or more severe compared to other variants. The delta variant remains the dominant strain worldwide and in Ohio.