Pfizer vaccines protect against the Omicron variant of Covid-19, with two doses offering 70% protection against severe disease and admission to hospital, a large real-world study by Discovery Health and the SA Medical Research Council (SAMRC) shows.
Preliminary results of the world’s “first at-scale real-life study” show the risk of hospitalisation is lower with Omicron infections than with previous variants of concern.
The analysis finds that the “severity of Omicron is 29% lower” among the general population, compared to the first wave of infections, Discovery revealed at a briefing on Tuesday.
Discovery Health CEO Dr Ryan Noach said people who are fully vaccinated with double-dose Pfizer-BioNTech shots have “high levels of protection from serious illness … across age groups and in the face of a range of chronic illness”.
But the risk of reinfection with Omicron is “relatively high” among those who have previously been infected with other variants of Covid-19 this year, the researchers noted.
The effectiveness of the double-dose Pfizer vaccine against becoming infected dropped from 80% against previous variants to only 33% against the Omicron variant.
Noach also noted that the number of paediatric admissions were low but the risk was higher than in the first wave.
“[The Omicron variant] may pose a risk of greater severity to children under 18. There is a 20% higher admission rate relative to in the first wave but the admission rate itself is low,” said Noach, noting that these admissions were “settling down” as the wave progressed.
About 78,000 pathology test results for Omicron infection, vaccination results and clinical results from Discovery Health’s data from November 15 to December 7 were the basis of this research.
SAMRC president Prof Glenda Gray and its scientists teamed up with Discovery’s health informatics analysts, led by chief health analytics actuary Shirl
Noach noted that the preliminary results could change over time, given that these findings are from the first three weeks of the Omicron wave.
The variant, identified late in November, is driving SA’s fourth wave of infections and is highly transmissible.
But, as the latest analysis confirms, hospital admissions have so far been significantly lower and decoupled from the pace of infections with the Omicron variant, in contrast with previous waves.
When SA scientists shared their information about the Omicron variant internationally, world leaders responded with panicked and unscientific travel bans.
The clinical and anecdotal reports and data collected so far suggest the Omicron variant may cause the mildest symptoms of all the variants of concern.
“At this early point we believe there is hope that the severity is lower [with this Omicron wave],” said Dr Noach.