5 key takeaways: Real-world Omicron data show level of vaccine efficacy

As Canada braces for a spike in Omicron cases, a study out of South Africa suggests Pfizer’s vaccine may not be as effective at preventing infection by the variant, but does hold up against severe disease.

Scientists have raced to uncover data about Omicron since its emergence was first flagged last month. South Africa’s daily infections have now risen to 20,000 COVID-19 cases.

The real-world study is considered preliminary, but does offer some evidence as public health officials prepare to deal with a surge.

Five key findings of a study of cases in South Africa from Nov. 15 to Dec. 7 are:

1. Protection from two doses of Pfizer’s mRNA vaccine slumped to 33 per cent, compared to 80 per cent previously

2. Protection of the vaccine against severe illness, measured as hospital admissions, is 70 per cent, compared to 93 per cent in the wave of Delta infections

3. Omicron seems to pose a higher risk of re-infection than previous waves

4. Children appeared to have a 20 per cent higher risk of hospital admission with complications, but this is very early data, with few cases, and so require careful follow-up to validate

5. Scientists say to have a clear portrait of the impact of Omicron, it is important to study how the variant behaves in other countries, other populations.