A growing body of preliminary research shows that Covid vaccines used in most parts of the world offer little or no protection against infection with the highly contagious Omicron variant.
All vaccines continue to provide significant protection against serious diseases from Omicron, which is the most important goal. But only the booster-boosted Pfizer and Moderna vaccines appear to be effective in stopping infections, and these vaccines are not available in most parts of the world.
Early studies show that other vaccines, including vaccines from AstraZeneca, Johnson & Johnson, and vaccines made in China and Russia, have hardly stopped the spread of Omicron. And since most countries have built their vaccination programs around these vaccines, this gap could have a major impact on the course of a pandemic.
A global surge in infections in a world where billions of people remain unvaccinated is not only threatening the health of vulnerable people, but increasing the possibility of even more options emerging. The disparity in the ability of countries to cope with the pandemic is almost certain to widen. And news of the limited effectiveness of the vaccine against Omicron infection could reduce the demand for vaccinations throughout the developing world, where many people are already hesitant or concerned about other health problems.
Most of the evidence so far is based on laboratory experiments that do not cover the full spectrum of the body’s immune response, and on tracking the effects on populations in the real world. However, the results are amazing.
Pfizer and Moderna pricks use new mRNA technology that consistently provides the best protection against infection, whatever the option. All other vaccines are based on older methods of triggering an immune response.
The Chinese vaccines Sinopharm and Sinovac, which account for nearly half of all vaccinations in the world, provide virtually zero protection against Omicron infection. The vast majority of people in China received these images, which are also widely used in low- and middle-income countries such as Mexico and Brazil.
A preliminary efficacy study in the UK showed that Oxford-AstraZeneca was unable to stop omicron infection six months after vaccination. Ninety percent of vaccinated people in India received this vaccine under the brand name Covishield; it was also widely used in most of sub-Saharan Africa, where Covax, the global Covid vaccine program, has distributed 67 million doses of vaccine to 44 countries.
Researchers predict that the Russian Sputnik vaccine, which is also used in Africa and Latin America, will show similarly dismal performance against Omicron.
African demand for Johnson & Johnson’s vaccine has skyrocketed because its single-dose regimen allows the vaccine to be easily delivered in resource-limited settings. But it also showed little ability to block Omicron infection.
Antibodies are the first line of defense induced by vaccines. But the shots also stimulate the growth of T cells, and preliminary research suggests that these T cells still recognize the Omicron variant, which is important in preventing serious illness.
“In the first place, you lose protection against asymptomatic mild infection, much better you retain protection against serious illness and death,” said John Moore, a virologist at Weill Cornell Medicine in New York. He called it a “silver lining,” which makes the Omicron seem less deadly than the Delta for now.
But that protection will not be enough to prevent Omicron from causing global turmoil, ”said J. Stephen Morrison, director of the Center for Global Health Policy at the Center for International and Strategic Research.
“The sheer scale of the infection will overwhelm health systems simply because the denominator is potentially so large,” he said. “If there is an outbreak of infection all over the world, shock, what will the world look like on the other side of it? “The war is over” or “The war has just entered a new phase”? We haven’t started thinking about any of this yet. “
People with breakthrough may experience only asymptomatic infection or mild illness, but they can pass the virus on to unvaccinated people, who can become more seriously ill and become a source of new options.
Dr. Seth Berkeley, executive director of Gavi, the global vaccine alliance, said more data is needed before conclusions are drawn about the effectiveness of Omicron vaccines, and that accelerated vaccination should remain the focus of the pandemic response.
Preliminary data from South Africa show that there is a much higher chance of reinfection with Omicron in people who already had Covid than with the original virus and previous variants. But some public health experts say they believe countries that have already weathered brutal waves of Covid, such as Brazil and India, may have a buffer against Omicron, and post-exposure vaccination produces high antibody levels.
December 18, 2021 10:26 PM ET
“The combination of vaccination and exposure to the virus seems to be stronger than a simple vaccine,” said Ramanan Lakshminarayan, an epidemiologist based in New Delhi. He noted that in India, the adult vaccination rate is only about 40 percent, but in some regions 90 percent is affected by the virus.
“There is no doubt Omicron will overwhelm India,” he said. “But hopefully India is protected to some extent thanks to vaccinations and contamination.”
China does not have the level of protection to support its weak vaccines. Due to China’s aggressive efforts to stop the spread of the virus within its borders, relatively few people have previously been infected. It is estimated that only 7 percent of people in Wuhan, where the pandemic began, have been infected.
Most Latin American countries relied on Chinese and Russian vaccines, as well as AstraZeneca. Mario Rosemblatt, professor of immunology at the University of Chile, said more than 90 percent of Chileans received two doses of the same vaccine, but the vast majority of them were the Coronavac vaccine, the Sinovac vaccine. The high vaccination coverage, combined with early reports that Omicron does not cause serious illness, is leading to a false sense of security in the country, he said.
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“We have to make people understand that this is not the case: if you have a high transmissibility, you will have a saturation of the health care system, because the number of cases will be higher,” he said.
Brazil recommended that all vaccinated people get a third dose, and it started using Pfizer’s vaccine for all boosters, but only 40 percent of those vaccinated came for the extra vaccine. Dr. Amilcar Tanouri, a virologist at the Federal University of Rio de Janeiro, said with cautious optimism that high levels of previous Covid infection could weaken the impact of Omicron, but noted that the most vulnerable Brazilians who were vaccinated first received coronavac, and tens of millions more were given away. AstraZeneca.
Mr Morrison called Omicron’s ability to evade vaccine defenses “a huge setback” for low- and middle-income countries, where, despite any discussion of boosters, the focus remains on securing the first vaccinations.
“The world is divided into two parts, right?” he said. “These are the ones who have a fast track to boosters versus those who have had very limited progress, and suddenly they fall prey to this new flogging.”
Just 13 percent of people in Africa have received at least one dose of the Covid vaccine.
Dr. Lakshminarayan said the Indian government, for which he sometimes serves as an advisor, is considering revaccination, but the Delta option still poses a significant threat to India, and two doses of the vaccine provide protection against Delta. This presents the government with a difficult choice: to focus on getting people who have not yet been vaccinated or partially vaccinated, up to two doses, or trying to get revaccinated for the elderly and people with high-risk diseases as protection against Omicron.
Morrison said news that mRNA-free vaccines do not provide adequate protection against Omicron infection could further erode demand for vaccines in countries that are already trying to create demand.
“This casts doubt on the full value of the vaccines,” he said. “If you fall behind that much and then suffer from it, it fuels anti-vaccine sentiment and weakens self-confidence.”
Tolbert Nienswa, a senior fellow at the Johns Hopkins Bloomberg School of Public Health, said the emerging threat to countries in the south of the world that rely on mRNA-free vaccines is an accusation of the failure of rich countries to share this technology or help build manufacturing. points in low- and middle-income countries.
As a consequence, dangerous options will continue to emerge in areas with low vaccination coverage and prolong the pandemic, predicted Dr. Nienswa, who was the deputy minister of health in Liberia during the worst Ebola outbreak in the country.
Dr. Berkeley of Gavi said it would be a grave mistake for countries to slacken vaccination efforts or assume that only mRNA vaccines are worth distributing.
“We may be seeing a situation where countries say, ‘If developed countries do not want these vaccines, then we do not want these vaccines,” he said. “It would, of course, be a misinterpretation if it turns out that these vaccines prevent serious illness and death.”
Linsey Chutel… Karl Zimmer and Emily Schmall made reporting.