Although the Tuesday findings are preliminary and not peer-reviewed, which is the gold standard for scientific research, they do match other early data on omicron behavior. One example being that it appears to be more easily transmitted.
Experts cautioned, however, that it was too early to draw conclusions on the outcome of omicron because the variant is still very new and hospitalizations may lag weeks behind infections.
Two doses of Pfizer BioNTech vaccine were given to people who had not been vaccinated. However, they showed 33% less protection from infection than those who were vaccinated. There was 70% protection against hospitalization according to an analysis by Discovery Health, South Africa’s largest private insurer and the South African Medical Research Council.
The study didn't include booster shots. Although they aren't yet common in South Africa, data from other countries has shown that they provide better protection.
Based on more than 211,000 COVID-19 results, the analysis in South Africa was done from Sept. 1, 2009 to Dec. 7, 2009. 41% of these were for adults who had received at least two doses of Pfizer's vaccine in South Africa.
The study divided the samples into two periods. These were those that were taken before Oct. 31, when Omicron was not likely to be very common in South Africa, as well as those taken after Nov. 15, when it was growing in popularity. This latter group was used to measure the effect of the omicron variant.
According to Dr. Ryan Noach of Discovery Health, experts now believe that omicron is responsible for more than 90% in South Africa's new infections. It is also growing in popularity in other countries.
Around the globe, researchers are trying to determine what this variant means for the coronavirus pandemic. This is well into its second-year. Pfizer announced Tuesday that the experimental pill it has developed to treat COVID-19 -- apart from its vaccine -- is effective against omicron.
South Africa has seen rapid spread of the virus in the few weeks since it was first detected. According to Johns Hopkins University, the seven-day average number of new cases per day in South Africa rose from 8.07 per 100,000 people Nov. 29 to 34.37 per 100,000 on Dec. 13. During the same time, the death rate has not increased.
Many people are looking for clues to what the future holds for the world.
"The fourth wave of omicron-driven new infections has a much steeper trajectory than previous waves. Noach stated that national data showed an exponential rise in new infections and test positive rates over the first three weeks, which indicates a highly transmissible variant of infection with rapid community spread."
The analysis shows that, despite increasing numbers of cases, hospital admissions for adults with COVID-19 are 29% less than the wave in South Africa's mid-2020. This is after accounting for the adjustment for vaccination status.
The study shows that those who had received two doses Pfizer vaccine were protected against infection by 33% in the first week of South Africa's current, omicron-driven wave. This is a substantial drop from the 80% protection provided during earlier periods.
The study also showed that 70% of people who were fully vaccinated by Pfizer were protected against hospital admissions during the omicron surge. This is a decrease from the 93% protection that was seen in South Africa's Delta-driven wave.
The study showed significant protection against hospital admissions even for older age groups. It found 67% for those aged 60-69, and 60% for those aged 70-79.
Some say that there isn't enough data to draw general conclusions about hospitalizations or the severity of omicron-related diseases.
"Their analyses cover only three weeks of data. It is therefore important not to infer too much at this time," Dr. Michael Head (Senior Research Fellow in Global Health, University of Southampton) wrote about the study.
He wrote that although South Africa's results suggest that omicron can cause milder diseases, Danish reports show the contrary. The findings can be affected by many factors, including previous infections and age.
Head asked, "Is Omicron milder or more severe than Delta?" The truth will come out over time. It will be revealed by the world's top scientists, many of them from the global south, such as South Africa. National-level decision-makers must accept that discretion is better than valor for now.
The South African analysis supports an earlier assessment made by U.K. authorities.
According to the U.K. Health Security Agency, Friday's data confirms that omicron can be transmitted more easily than other variants. Studies have shown that the AstraZeneca vaccine and Pfizer vaccines do not prevent symptomatic infections among people who are exposed to omicron. However, preliminary data indicate that they may be more effective at preventing them.
This story has been updated with the correct time period the samples were taken. They were dated Sept. 1 through Dec. 7, and not Nov. 15 to December 7. The news release also clarifies that not all samples were positive as Discovery originally stated.