If Omicron is less severe, why are COVID-19 deaths rising?

From Russia to Brazil, record COVID-19 case numbers are being reported as the Omicron variant continues to spread across the globe.

And deaths are continuing to rise too. On 28 January, Australia suffered its deadliest day of the pandemic so far, with nearly 100 deaths.

In the US, Omicron is claiming an average of 2,200 lives each day – higher than the Delta variant, which peaked at a seven-day average of 2,078 in September last year, according to Reuters analysis.

But scientists have found that Omicron is less severe than the Delta variant, and more people are vaccinated now – with the number of vaccine doses distributed globally at more than 10 billion.

So why are so many people still dying?

As we’ve seen throughout the two years of the pandemic, deaths lag behind rises in case numbers, so we’re likely to see increasing death numbers as Omicron cases continue to climb in some countries, including Russia and Brazil.

Omicron has been found to spread much more quickly than the previously dominant Delta variant – with studies suggesting it’s four times more transmissible.

Most of those who are dying from Omicron in the US are unvaccinated, showing that vaccines do make a difference in reducing hospitalization and deaths.

"More infectious variants tend to run through a population very rapidly," Wafaa El-Sadr, a professor of epidemiology and medicine at Columbia University in New York City, told Reuters. "Even if such new variants cause less severe disease (particularly among those vaccinated and boosted), we will likely still see an increase in hospitalizations and deaths due to the vulnerability of the unvaccinated and unboosted.

“It will be a while until we see a decrease in deaths as very sick people with COVID remain hospitalized for a long time," she said.

“We have increasing information that Omicron is less severe than Delta, but it is still a dangerous virus,” says the World Health Organization’s Dr Maria Van Kerkhove, in a recent video explaining the impact of the variant.

“We are learning that people with underlying conditions, people with advanced age, people who are unvaccinated can have a severe form of COVID-19 following infection from Omicron.

“We know that people are still being hospitalized [with Omicron] as well as dying, so it’s important we have information out there that is accurate, that does suggest it is less severe than Delta, but it is not mild.”

Hospitals around the world have struggled with the number of admissions as Omicron cases surged in December and January. In the US and UK, the military were sent to help support hospitals tackling staff shortages.

Reuters tallys showed COVID-19 hospitalizations setting records in some US states in January, including Arkansas and North Carolina.

Healthcare systems buckling under the weight of cases will inevitably find it harder to save lives.

“Omicron is overtaking Delta in terms of circulation and it is very efficiently transmitted between people,” says Dr Van Kerkhove. “This is putting a significant burden on our healthcare systems, which are already significantly overburdened given that we’re entering into the third year of this pandemic.

“And if people can’t receive the proper care that they need, then more people will end up with severe disease and dying, and that’s something we want to prevent.”

Get vaccinated, but still take other measures to reduce transmission and illness, says Dr Van Kerkhove.

“We know that vaccination is incredibly protective against severe disease and death, but it also does prevent some infections and some onward transmission, but it’s not perfect in terms of preventing infections and transmission.

“This is why we also recommend people protect themselves against exposure. Physical distancing, wearing of a well-fitted mask over your nose and mouth, making sure you have clean hands, avoiding crowds, working from home if you can, getting tested and making sure you seek care where needed – all of those measures, this layered approach, are ways in which you can keep yourself safe and protect yourself from getting infected and passing the virus on to somebody else.”

The more this virus circulates, the more opportunities it has to change, says Dr Van Kerkhove.

So another reason to take protective measures is to reduce the risk of further variants that would prolong the pandemic – and cause more deaths.

“Omicron will not be the last variant that you will hear us discuss, and the possibility of future emergence of variants of concern is very real. And … we don't [yet] understand what the properties of those variants may be,” she says.

“Certainly, they will be more transmissible because they will need to overtake variants that are currently circulating. They could become more or less severe, but they could also have properties of immune escape. So we want to reduce the risk of future emergence of variants of concern.”