Early data on Omicron show surging cases but milder symptoms – The Economist

Dec 11th 2021T WO WEEKS after the Omicron variant was recognized, healthcare facilities are bracing for a covid-19 tsunami. In South Africa, where it has displaced Delta, cases are increasing faster than in earlier waves. Each person with Omicron may infect 3-3.5 others. Deltas latest rate in the country was 0.8. The Economist todayHandpicked stories, in your inboxA day-to-day newsletter with the finest of our journalismSouth Africa is not in lockdown, which may partly explain Omicrons fast spread. However, previous versions benefited from encountering lots of people with no resistance. By now, most South Africans have either recuperated from covid or been vaccinated.In such an environment, there are 2 methods Omicron might spread so quick. One is greater infectiousness, which depends upon such factors as how easily it goes into cells. The other is better evasion of immunity.The Delta alternative ended up being dominant mainly due to the fact that of its transmissibility. On the other hand, Omicron seems to have benefits in both areas. Anecdotal evidence for its higher contagiousness is mounting: super-spreader events after which 35-78% of individuals tested positive have happened in Norway, Denmark, Spain and Britain.Moreover, Omicron has unprecedented capability for reinfection. A current study led by Juliet Pulliam of Stellenbosch University showed that the number of South Africans who check favorable at least 90 days after their last favorable test is more than you would anticipate based upon earlier waves. And antibodies produced by Pfizers vaccine are less effective versus Omicron than versus earlier versions. However, they still accomplished strong neutralisation in people with booster jabs or prior infections. Existing vaccines may offer excellent security versus serious illness triggered by Omicron.Data on virulence are more heartening. In hospitals Omicron has not yet shown a pattern of worse illness in older people. Among covid-positive medical facility clients in the South African city of Tshwane, 70% of those aged 50-69 and 90% of over-80s had serious cases throughout the Delta wave. This share is now around 30% for all ages.The typical severity of Omicron cases might rise. One possible factor is that Omicrons anomalies yield milder health problem if it does not. This would partially balance out the impact of a rise in cases, though death rates could yet increase if wards are overwhelmed. Another explanation is that many older South Africans got jabs in current months. Omicron would present a severe hazard to the unvaccinated if this is the cause. ■ Sources: NICD, South Africa; Trevor Bedford; “Increased danger of SARS-CoV-2 reinfection related to introduction of the Omicron version in South Africa”, by J.R.C. Pulliam et al. (working paper) This post appeared in the Graphic information area of the print edition under the heading “Mixed signals”

Dec 11th 2021T WO WEEKS after the Omicron version was identified, healthcare facilities are bracing for a covid-19 tsunami. By now, most South Africans have actually either recuperated from covid or been vaccinated.In such an environment, there are 2 ways Omicron might spread so fast. And antibodies created by Pfizers vaccine are less reliable against Omicron than versus earlier variations. ■ Sources: NICD, South Africa; Trevor Bedford; “Increased danger of SARS-CoV-2 reinfection associated with introduction of the Omicron variation in South Africa”, by J.R.C. Pulliam et al. (working paper) This post appeared in the Graphic detail area of the print edition under the heading “Mixed signals”