The First Large-Scale Study on Omicron is Out

Photo by Andrea De Santis on Unsplash.

Since Omicron was first detected in southern Africa late November — prompting widespread travel restrictions on the region —information on the new variant has been lacking. But as cases rise data grows and the the first large-scale study on Omicron has just been released.

On December 14th, Discovery Health — a South African private health insurance administrator — in collaboration with the South African Medical Research Council, released the results of their analysis on the country’s Omicron outbreak — which have yet to be published and peer-reviewed. A study based on over two hundred positive COVID-19 cases, where more than one third of these cases was reported during the Omicron-driven forth wave of infections in South Africa.

Their study shows that during this wave the rates of reinfection increased and (since the new variant currently accounts for 90% of new infections) this suggests that Omicron poses a higher risk of reinfection, when compared with previous variants. There are two possible reasons behind this: one being that reinfections have simply been rising over time as the immunity provided by a first infection wanes, the second being that the mutations observed on Omicron may allow it to better evade the immune system. The reality is likely a combination of both.

Despite the higher infection rates which caused a twenty fold rise in positive cases in South Africa, within two weeks of the new variant’s announcement, hospital admissions have remained stable which means that Omicron infections appear to be less severe; although the true severity of Omicron may be hidden by the high seroprevalence levels of SARS-CoV-2 neutralizing antibodies in the general population. Sadly, children do appear to be more susceptible to complications arising from infection with the new variant. None-the-less, it is worth considering the possibility that the virus is evolving towards becoming less pathogenic and endemic — i.e. permanently circulating within the population. A scenario which has been hypothesized by many scientists.

Regarding the new variant’s impact on the efficiency of vaccination, the Pfizer-BioNTech vaccine showed a 33% protection against infection with SARS-CoV-2 during the Omicron-driven fourth wave of COVID-19. A significant decrease from the 80% previously reported during the Delta-driven third wave. However, its important to note that the main goal of the vaccines is not to prevent infections but to prevent hospitalizations. Here, the results are much more encouraging, as the vaccines provide 70% protection against hospital admission. Although it has also decreased from the former 93%, protection against hospitalization remains remarkably high and is maintained across all ages.

Overall, there are bad and good news. Given the higher infection rates of Omicron it is likely that countries exposed to the new variant, where vaccination rates are low, will see an increase in cases and Omicron-related deaths — which is why the European Centre for Disease Prevention and Control maintains that Omicron poses a very high risk. On the bright side, Omicron appears to be less severe when compared to previous variants while vaccines remain effective in preventing hospitalizations and the best available tool against the global COVID-19 pandemic.

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Gil Pires

Gil Pires

Junior Consultant | MSc in Biotechnology