The rise in cases in South Africa after the arrival of omicrons does not overwhelm hospitals
Vaccines from Pfizer Inc. provides less immunity to the omicron variant than other major versions of Covid-19, according to laboratory experiments showing that a third dose can help suppress the highly mutated strain.
Researchers at the African Health Research Institute in Durban, South Africa, found that omicrons reduced the levels of neutralizing antibodies produced by people who received two doses of Pfizer-BioNTech SE, compared with the strain of omicron. was discovered in China almost two years ago.
Alex Sigal, lead researcher at the lab, said in an online presentation of the first reported experiments that evaluated the vaccine’s effectiveness against the new variant, the loss of protection. immunity is “strong, but incomplete”.
“There will be more breakthroughs in vaccine-induced immunity,” says Sigal. “A good booster shot can reduce your risk of infection, especially severe infections that lead to more severe illness. People who haven’t had a booster shot should get one, and people who have already been infected should get a booster shot. should be vaccinated before that.”
Representatives for Pfizer and BioNTech, the first Covid vaccine manufacturers notified in the US, did not immediately respond to requests for comment. The study could add to the debate about whether there is an early need for an omicron-targeted vaccine, fine-tuned to continue to effectively fight the pandemic. Moderna Inc. President Stephen Hoge. said there was a risk that existing vaccines would be less effective against the strain of the virus, although US health adviser Anthony Fauci said the severity of illness caused by the variant could be compromised. limit.
The rapid spread of Omicron in South Africa has raised concerns that immune protection from vaccination or a previous wave of Covid-19 may not be enough to prevent reinfection or avert a wave. new cases and hospitalizations. The World Health Organization has warned omicrons can have “serious consequences” amid signs that it makes the coronavirus more contagious.
Cautious optimism
However, the surge in cases in South Africa following the emergence of omicrons has so far not overwhelmed hospitals, leading some to be optimistic that the new strain of bacteria could cause mild illness.
Since South Africa announced the discovery of omicrons on November 25, about 450 researchers globally have worked to isolate this variant from clinical samples, culture it in the lab, verify the process. its genetic makeup and established methods to test it in plasma samples, according to WHO.
Sigal’s lab work involved testing 14 plasma samples collected from dozens of people who had received a second Pfizer-BioNTech injection about a month earlier to assess the levels of antibodies needed to neutralize the virus. disable or stop the virus. Sigal said levels of neutralizing antibodies against omicrons were significantly higher in a small group of participants who had had Covid about a year earlier.
That’s “promising,” said John Wherry, director of the Institute for Immunology at the University of Pennsylvania’s Perelman School of Medicine. That means an additional dose of existing vaccines would increase the level of neutralizing antibodies to omicrons, although more data is needed to confirm that, he said.
Results are preliminary, and the exact extent of immune escape can vary, Sigal said. The results, along with those from other labs studying the strain, will help determine whether existing Covid vaccines need to be modified to protect against omicrons.
Sigal’s lab was the first to isolate the beta variant, a coronavirus strain identified in South Africa in late 2020. He noted that omicrons escape antibody neutralization more easily than beta, which considered to be the most avoidant type of immunity among the previously discovered variants of concern.
