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Sinovac Booster Provides Elderly Stronger Protection Against Omicron,


Two doses of China’s Sinovac vaccine gave the elderly only moderately high levels of protection against severe illness and death from Covid-19, but a third dose significantly strengthened their defenses. New study by scientists in Hong Kong.

The study is based on patients infected during the current devastating period. Omicron wave in Hong Kongserves as a warning note for mainland China, where Sinovac is a pillar of the country’s vaccination program. Many older people out there have yet to receive booster shots.

The study found that for people aged 60 and older, two doses of Sinovac were 72 percent effective against severe or fatal Covid-19 and 77 percent effective against COVID-related death. These levels of protection were lower than those provided by two doses of Pfizer-BioNTech. The same study found that it was 90 percent effective against severe or deadly Covid and 92 percent effective against death among Hong Kong residents of the same age group.

The study proved that the Sinovac booster vaccine helped significantly and was 98 percent effective against severe or fatal Covid in people who were at least 60 years old.

Yanzhong Huang, a global health expert at the Council on Foreign Relations, said the results highlight the urgency for mainland China to step up its belated support campaign. “The government has a lot of work to do to make sure this segment of the population gets the booster vaccines,” he said.

The study’s authors, scientists from the University of Hong Kong, noted that the city’s booster program has begun recently, making it difficult to determine how long protection from a third dose will take.

They said that because people with underlying health conditions in Hong Kong are more likely to resist vaccination, those who choose to vaccinate or be vaccinated are also likely to be healthier in the first place, inflating estimates of how protective the vaccines are initially.

Sinovac, a privately owned Chinese company that makes the vaccine, is one of two Covid vaccine manufacturers based in China. Vaccines using mRNA technology, such as those made by Pfizer-BioNTech and Moderna, are not available there.

The new study highlights the possible ramifications for China, which is largely based on Sinovac and is battling the biggest Covid outbreak in two years. More than 87 percent of the Chinese population has been vaccinated. But Zeng Yixin, deputy minister of the National Health Commission, said just over half of people aged 80 and over have recently been vaccinated twice, with less than 20 percent of people in this age group receiving a boost.

The new study in Hong Kong received funding from the Chinese Center for Disease Control and Prevention as part of what one of the study’s co-authors described this week as an effort to understand the comparative effectiveness of vaccines. It has been published online as a preprint, but has not yet been reviewed by peer scientists for publication in a scientific journal.

In the study, Sinovac’s vaccine performed similarly to Pfizer’s among teens, even without the booster dose. In people under 60, two doses of Sinovac were roughly 92 percent effective against severe or deadly Covid, while two doses of Pfizer were about 95 percent effective.

Although Pfizer offers more than Sinovac’s and a booster dose significantly increases protection levels, neither vaccine has offered much protection against mild or moderate Covid. During the most recent wave, people in Hong Kong were largely infected by the following sub-variant. Omicron, known as BA.2. Like other versions of Omicron, BA.2 infected many vaccinated people.

The Hong Kong wave has been killing people at a rate that has surpassed that of nearly every country since the coronavirus emerged – a large part of this as a result of low vaccination rates among older residents. Nearly 90 percent of the people who died in the last wave were not fully vaccinated, meaning it’s more important to get the most vulnerable people vaccinated than a particular brand of vaccine.

Like Hong Kong, mainland China largely managed to curb transmission of the virus before Omicron, leaving its population with little immunity to previous infections.

Beyond China, Sinovac vaccines are critical in protecting people against severe Covid, especially in poorer countries. The vaccine is used in 49 countries, including South America and Africa.

But concerns about the protection it offers had already mobilized the World Health Organization. I recommend in October Recipients 60 years of age and older receive a third dose.

D., an infectious disease specialist at Sinai Health and University Health Network in Toronto, who was not involved in the Hong Kong study. Andrew Morris said the results are consistent with the following. laboratory studies It suggests that Sinovac produces lower levels of neutralizing antibodies than mRNA vaccines such as Pfizer’s.

“I think in countries that rely heavily on Sinovac, they will likely be struggling with high infection rates, especially if they don’t have an mRNA enhancer or even support with Sinovac. This is the last wave of BA.2,” he said.

Dr. The results in Hong Kong, like those from other vaccine studies, also depend heavily on how long it has been since the vaccines were administered to humans, Morris said. Protection tends to weaken over time.

From the Council on Foreign Relations, Dr. Huang said the results of the latest study on the efficacy of third doses of Sinovac can be taken by Chinese leaders as an encouraging sign that Chinese-made vaccines can continue to be the focus of immunization campaigns.

“Now, they don’t need to face strong pressure for Chinese leaders to approve BioNTech’s vaccine,” he said.



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