Discovery Health on Tuesday said its research shows the effectiveness of the two-dose Pfizer-BioNTech Covid-19 vaccination in preventing severe disease and hospitalisation as a result of Omicron variant infection.
The research was carried out by Discovery Health’s actuarial team in collaboration with leading scientists at the South African Medical Research Council (SAMRC).
Last month scientists in South Africa were the first to detect the new Covid-19 variant now named “Omicron”.
“We used a test-negative design methodology to establish the Pfizer-BioNTech Covid-19 vaccine’s real-world effectiveness against hospital admission from Omicron infection,” says Shirley Collie, Chief Health Analytics Actuary at Discovery Health.
“We carried out three carefully constructed sensitivity analyses, with consistent results across each analysis supporting the veracity of our findings.
“These findings were reviewed by scientists at the SAMRC with whom we have collaborated in multiple areas of our pandemic-related research to date.”
Discovery Health said the result shows that vaccinated individuals who received two doses of the Pfizer-BioNTech vaccine had 33% protection against infection, relative to the unvaccinated, in the first weeks of South Africa’s Omicron-driven fourth wave.
“This represents a significant drop from the 80% protection against infection afforded during the earlier period, probably on the basis of lower antibody susceptibility, following the extensive spike protein mutations in the Omicron variant,” said Discovery Health.
“Encouragingly, though, the result shows that these same vaccinated individuals who received two doses of the Pfizer-BioNTech vaccine had 70% protection against hospital admission in this same time period.”
While protection against hospital admission reduced from the highs of 93% in South Africa’s Delta-driven wave, 70% is still regarded as very good protection.
President of the SAMRC, Professor Glenda Gray, said: “We are extremely encouraged by the results of Discovery Health’s analysis.
“It is extremely important to be able to demonstrate to the public that in a real-world setting – in the presence of a highly transmissible new Covid-19 variant – the Pfizer-BioNTech vaccine provides good protection against severe disease and hospitalisation.”
Furthermore, the analysis demonstrates that protection against hospital admission is maintained across all ages, in people from 18 to 79 years, with slightly lower levels of protection for the elderly (67% in people aged 60 to 69 and 60% for people aged 70 to 79).
Protection against admission is also consistent across a range of chronic illnesses, including diabetes, hypertension, hypercholesterolemia and other cardiovascular diseases.
The research shows that Omicron reinfection risk is significantly higher compared to prior variants.