People who have recovered from a contagion with omicron, the new variant of the coronavirus, could be protected from subsequent infections caused by the delta variant, according to a new laboratory study by South African scientists.
If other experiments confirm these findings, there would be signs to consider a less dire future for the pandemic. In the short term, the omicron variant is expected to generate a wave of cases that will put significant pressure on economies and healthcare systems around the world, but new research suggests that in the long term, in a world dominated by omicron, it could have fewer hospitalizations and deaths than in one where the delta variant continues to wreak havoc.
“Omicron is likely to outperform delta,” said Alex Sigal, a virus expert at the African Institute for Health Research in Durban, South Africa, who led the new study. “Perhaps the fact that delta is no longer the dominant variant is a good thing and we are dealing with something that we can easily live with and that will disturb us less than the previous variants.”
This week, Sigal published the research in the institute website. It is not yet published in a scientific journal.
Independent scientists said that while the results of the South African experiment are preliminary, they are robust. Carl Pearson, a public health researcher at the London School of Hygiene and Tropical Medicine, said the results were in line with what is currently happening in the UK.
“Omicron comes in and grows fast, and the delta trend becomes downward,” Pearson said.
Nathan Grubaugh, an epidemiologist at the Yale School of Public Health, said he was seeing the same pattern in Connecticut. “We see that omicron increases exponentially, while the cases of delta decrease,” he said. “This suggests to me that omicron is competing with delta in terms of susceptible individuals, leaving them less susceptible to delta and reducing the cases of this variant.”
When people started getting the coronavirus two years ago, they produced antibodies and immune cells that could provide protection. Because of that, it was very rare for a person to become infected again in the following months.
But, in late 2020, new variants of coronavirus emerged. Some, like alpha, had mutations that allowed them to spread rapidly. Others, like beta, had adaptations that allowed them to evade antibodies, either produced during a previous infection or in response to a COVID-19 vaccine.
The delta variant, which rose to prominence last summer, had mutations that gave it a greater ability to spread and a moderate ability to evade antibodies. Vaccines were still effective against delta, but not as effective as in the early days of the pandemic.
In November, when omicron appeared, it spread faster than delta. The researchers suspected that its speed had two origins. Somehow it was able to transmit quickly, perhaps replicating itself in large numbers or spreading more easily from one person to another. Ómicron also infected vaccinated people and those who had become ill with the previous variants.
In another study conducted this month, Sigal’s team, as well as other research groups, confirmed omicron’s ability to evade antibodies from previous vaccines and variants. To do this, they analyzed the blood of people vaccinated or who had recovered from COVID-19, and mixed it with different variants.
Repeatedly, antibodies that were potent against delta and other variants did not work well against omicron. This helped explain why so many vaccinated and infected people were infected with omicron, albeit more mildly than those who were infected with delta.
In their new study, Sigal and his colleagues did the same experiment, but this time with people who had recovered from omicron infections. Despite the fact that South Africa has just experienced a huge spike in cases of this variant, Sigal and his colleagues were only able to study thirteen patients.
“It was very difficult because of the vacation period,” he said. “Nobody wants to stay to be part of a study.”
Seven of the patients were vaccinated and six were not. The scientists did not determine which volunteers had previously been infected with other variants of the virus; However, as the vast majority of South Africans suffered from the disease before the arrival of omicron, it is likely that most would not have caught COVID-19 for the first time with the latter variant.
As expected, the researchers found that the patients’ blood had a high level of strong antibodies against omicron, but those antibodies were also effective against the delta variant.
The Coronavirus Pandemic: Key Things to Know
This particularly surprised them because their study earlier this month showed that the opposite was not the case: Antibodies produced after a delta infection offered little protection against omicron.
As omicron travels one country after another, Sigal infers that it will give people immunity not only against this same variant, but also against delta. That would mean that people who get the delta variant will have fewer chances of transmitting the virus to other people. At the same time, omicron will easily infect people who have recovered from the delta variant. That competitive advantage could spell the end of delta.
Of course, this is speculation about the future health of billions of people based on just thirteen volunteers. Also, Sigal cannot say exactly what the benefit omicron provides against the delta variant is due to. The antibodies it produces may also act more broadly against other variants.
It is also possible that the infections with the omicron variant have simply aroused the existing immunity in the volunteers, acquired with the vaccines or previous infections. If that’s the case, it remains to be seen what will happen to unvaccinated people who become infected for the first time with omicron, a fate that millions of Americans could face in the coming weeks.
Although omicron ends with delta, that does not mean that this variant will prevail for generations. When people acquire immunity against the omicron variant, natural selection could favor mutations that produce a new variant that manages to evade that immunity.
Depending on the evolution of the coronavirus, Pearson said he could envision three different futures.
In one, the covid mimics the flu, with a seasonal variant that exceeds the previous one, year after year.
The second scenario is that it mimics dengue fever, coexisting several variants that evade different antibodies, which causes people to get sick in different periods of time when they are infected with any of these variants.
The third possibility is the most desirable: a variant wins out and becomes an easily preventable pathogen. But Pearson believes that is the least likely scenario.
“I bet we can rule out the trend where it comes down to a single strain that immunizes in the long run and turns into a childhood infection like measles,” he said. “However, it is also a possibility.”