The Omicron variant appears to cause fewer serious illnesses than previous versions of the coronavirus, and the Pfizer vaccine appears to offer less defense against infection but still provide good protection against hospitalization, according to analysis of data from South Africa where the new one Variation leads to an increase in infections.
Although the results are preliminary and not peer-reviewed – the gold standard in scientific research – they are consistent with other early data on Omicron’s behavior, including the fact that it appears to be more easily transmitted.
A two-dose vaccination from Pfizer / BioNTech appeared to offer only 33% protection against infection and 70% protection against hospitalization during the current Omicron wave in South Africa, according to analysis by Discovery Health, South Africa’s largest private health insurer, and the South African Medical Research Council.
The data was collected from November 15th to December 7th. During this time, omicron was first discovered by scientists in South Africa and Botswana and can change over time. Experts now say Omicron is responsible for more than 90% of all new infections in South Africa, said Dr. Ryan Noach, CEO of Discovery Health.
The country is experiencing rapid spread of the virus – concentrated in its most populous province, Gauteng. The seven-day moving average of daily new cases in South Africa has increased in the past two weeks from 8.07 new cases per 100,000 people on November 29 to 34.37 new cases per 100,000 people on December 13, according to Johns Hopkins University. The death rate has not increased over the same period.
“Compared to earlier waves, the fourth wave, controlled by omicrons, shows a significantly steeper course of new infections. National data show an exponential increase in both new infections and test positive rates in the first three weeks of this wave, suggesting a highly transmissible variant with faster spread of the infection in the community, ”Noach said.
Although the number of cases is increasing, hospital admissions are not increasing at the same rate, leading the scientists to report that the risk of hospitalization with Omicron is lower than with Delta or earlier variants. According to the analysis, adult hospital admissions diagnosed with COVID-19 are 29% lower than in the wave South Africa experienced in mid-2020 after vaccination status was adjusted.
The result shows that people who received two doses of the Pfizer vaccine had 33% protection from infection in the first few weeks of the current omicron-driven wave in South Africa. This is a significant decrease from the 80% protection against infection that was offered in previous periods.
The researchers say it’s encouraging that the study shows that people fully vaccinated with Pfizer have 70% protection from hospitalization during the omicron surge. That’s still a drop from the 93% protection seen in South Africa’s delta-driven wave.
The study shows a significant protection against hospital admissions even in older age groups with 67% in the 60- to 69-year-olds and 60% in the 70- to 79-year-olds.
The analysis was based on examining more than 211,000 positive COVID-19 test results, 41% of which were related to adults who received two doses of the Pfizer vaccine. Approximately 78,000 of the positive results were attributed to Omicron infections.
The South African analysis supports an earlier assessment by the UK authorities.
The UK health authority said Friday that new data from the UK confirm that Omicron is more easily transferable than other variants. Other studies suggest that both the AstraZeneca and Pfizer vaccines are less effective at preventing symptomatic infections in people exposed to Omicron, although preliminary data show that effectiveness increases to 70 to 75 after a third booster dose % seems to be increasing.
The study also found that Omicron posed a higher risk of reinfection. For people who were previously sick with COVID-19, the risk of reinfection with Omicron is significantly higher than with previous variants.
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