Two doses of Pfizer-BioNTech’s Covid-19 vaccine appear to provide 70 percent protection against hospitalisation from the Omicron coronavirus variant , according to an extensive real-world study in South Africa.

The analysis released on Tuesday by South Africa’s largest private health insurance administrator, Discovery Health, was based on more than 211,000 positive Covid-19 test results of adults from November 15 to December 7, about 78,000 of which were attributed to Omicron.

The 78,000 results are not confirmed Omicron cases, meaning the study is not able to draw conclusive findings about the new strain, which the World Health Organization (WHO) has labelled a “variant of concern”.

The discovery of Omicron was first announced in November by scientists in South Africa, and the country is the first to experience a surge in Covid-19 driven by the Omicron variant.

BREAKING [Thread]: 1. SA’s first real-world data on #Pfizer ’s #Covid19 jab’s protection @ #Omicron infection + hospitalisation via @Discovery_SA + @MRCza

Note: This is data from the 1st 3 weeks of the outbreak, so it might change – regard it as preliminary real-world data pic.twitter.com/7sfPzarZlX

— Mia Malan (@miamalan) December 14, 2021

South African scientists have so far confirmed about 550 Omicron sequences, with the variant accounting for 78 percent of sequences from November, a higher share than the previously dominant Delta variant.

The discovery of a new strain of the coronavirus last month triggered alarm that it could cause another surge in global infections, and led many countries to impose travel restrictions on the southern Africa region.

South Africa’s daily infections have since risen to almost 20,000 in recent days.

Based on analysis by Discovery’s clinical research and actuarial teams, and in collaboration with South Africa’s Medical Research Council (SAMRC), the real-world study calculated that two doses of Pfizer-BioNTech offered 70 percent protection against hospitalisation during the recent surge in cases and 33 percent protection against infection.

The level of protection is high considering that the WHO renders a Covid vaccine effective if it provides 50 percent protection .

The study cites data gathered from the first three weeks of South Africa’s Omicron-driven wave and may change as time passes.

The researchers emphasised that its findings are preliminary and not peer-reviewed. South Africa is using the Pfizer-BioNTech and Johnson & Johnson vaccines in its Covid-19 immunisation campaign, with more than 20 million Pfizer doses administered so far.

It concluded that there was a higher risk of reinfection during the fourth wave than during previous waves and that the risk of hospitalisation among adults diagnosed with Covid-19 was 29 percent lower than during the country’s first wave early last year.

Children appeared to have a 20 percent higher risk of hospital admission with complications during the fourth wave than during the first, despite a very low absolute incidence, it said. Discovery cautioned that the study’s findings should be considered preliminary.

Glenda Gray, SAMRC president, said it was important that the Pfizer-BioNTech vaccine appeared to be offering good protection against severe disease and hospitalisation.