And you have a one-in-four chance of catching Omicron from an infected person in your household.
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14 March
- Excess mortality figures reveal the true global cost of the pandemic.
- Household secondary attack rate 50% higher for Omicron than for Delta.
- Three doses of mRNA vaccine achieves nearly 50% greater protection against symptomatic infection than two doses.
The true death toll of the covid pandemic is estimated to be around three times higher than official figures, according to a study of excess mortality over the past two years.
A paper published in The Lancet presents the findings of a study of mortality statistics from 191 countries and 252 sub-national regions.
While the official death toll of covid was 5.94 million as of 31 December 2021, the analysis found the number of excess deaths – the number of observed deaths minus the number of expected deaths based on historical data and trends – was around 18.2 million.
This represented an extra 120 deaths per 100,000 people globally, but there were regional differences. For example, the largest numbers of excess deaths were seen in south Asia – particularly India – north Africa, the Middle East and eastern Europe.
At a country level, Russia showed the highest rate of excess mortality, followed by Mexico, Brazil and the US.
Australia, Iceland, Singapore, New Zealand and Taiwan all showed negative excess mortality rates, meaning that the observed number of deaths in 2020 and 2021 was actually lower than expected. However, this would have been before the recent Omicron surge.
The study wasn’t able to access enough data on causes of death to draw conclusions about why the excess deaths were occurring, but said “the magnitude of disease burden might have changed for many causes of death during the pandemic period due to both direct effects of lockdowns and the resulting economic turmoil”.
Household members of an Omicron-infected case have around a one-in-four chance of catching the infection, which is around 50% higher than for Delta, researchers have found.
A population-based study published in JAMA detailed the secondary attack rate among more than 31,000 Norwegian households with one index case of covid – either Omicron, Delta or unclassified – and more than 80,000 non-index household members.
This revealed that the secondary attack rate for Omicron was 25%, for Delta was 19% and for non-classified cases was 18%.
After adjusting for various factors, researchers calculated that the risk of infecting household members was 50% higher for Omicron than for Delta. The risk of secondary infections was also higher for men, unvaccinated household members, and those aged over 30 years.
Three doses of either Pfizer or Moderna vaccines are nearly 50% more effective at preventing symptomatic Omicron infection than two doses, a study suggests.
Writing in the New England Journal of Medicine, researchers report the outcomes of two matched retrospective cohort studies involving just over one million people who received two doses of the Pfizer vaccine, 281,000 who received a third booster dose of Pfizer, nearly 800,000 who had two doses of the Moderna vaccine, and nearly 93,000 who had three doses of Moderna.
The booster dose of Pfizer was nearly 50% more effective than two doses at preventing symptomatic infection with Omicron, and 76% more effective at preventing hospitalisation or death. Similarly, three doses of Moderna were 47% more effective at preventing symptomatic infection with Omicron than two doses, but there were not enough cases of severe Omicron infection to calculate its effectiveness against hospitalisation or death.
