Key role seen in year ahead for Chinese vaccines

Sinovac, Sinopharm expected to be among top global distributors in fight against COVID

Chinese vaccines are set to play a crucial role in fighting the COVID-19 pandemic in 2022, with new analysis pointing to the quality and quantity expected this year.

Under projections provided to China Daily by London-based science consultancy Airfinity, Chinese pharmaceutical companies Sinovac and Sinopharm are expected to be the third- and fourth-largest providers of COVID-19 vaccines this year.

Airfinity predicts that Sinovac will contribute 1.88 billion vaccines this year and Sinopharm will distribute 1.85 billion. By volume, both companies are expected to contribute more than vaccine powerhouses AstraZeneca (1.75 billion), Moderna (1.62 billion) and Johnson & Johnson (1.34 billion).

Pfizer will lead vaccine production this year, contributing 4.11 billion vaccine doses, while Novavax will emerge as a major player in global treatment production, contributing 2.44 billion doses, according to Airfinity's projections.

The consultancy also predicted that 19 major manufacturers will contribute a combined 16.71 billion doses this year. Of these, 3.8 billion, or 23 percent, will come from Chinese manufacturers, which also include CanSino Biologics (73.5 million).

Meanwhile, a new study from Oxford University found that the CoronaVac vaccine from Sinovac can be effectively boosted by a third vaccine of the same or different type. This is seen as a crucial feature of any successful vaccine at this point in the pandemic, as protection among the vaccinated begins to wane and new variants emerge.

In a study of 1,240 participants in Sao Paulo, Brazil, researchers established that a booster dose of any of the Pfizer, AstraZeneca, Johnson & Johnson or CoronaVac vaccines induces a significant increase in antibody levels in those who have previously received two doses of CoronaVac.

The results, which were published this week in a peer-reviewed paper in the medical journal The Lancet, showed that a heterologous-or mixed-vaccine schedule provoked the strongest immune reaction, including against the Delta and Omicron variants. The study also found that the mixed schedule with the strongest response consisted of two CoronaVac shots followed by a Pfizer booster.

"The new data presented here show the extraordinary response to a third dose of coronavirus vaccines in a heterologous vaccine schedule," said Sue Ann Costa Clemens, an infectious diseases specialist at the Oxford Vaccine Group and lead author of the paper. "These data will also guide other low- and middle-income countries in setting up the most optimal and affordable booster programs."

Because the CoronaVac vaccine is easy to transport and store, it is seen as an attractive option for distribution in remote and less-developed regions.

Meanwhile, another study released this month showed how effective the Sinovac vaccine is in getting outbreaks under control and communities in the developing world back on track.

Two years ago, health authorities in Colombia sent a research team to Mitu, an Indigenous community deep in the Amazon Basin, having received word of an unusually high infection rate for COVID-19.

The team of scientists led by the University of Cordoba in Colombia confirmed these suspicions. More than half of people tested had antibodies for the novel coronavirus, translating to one of the highest community seropositivity levels in the world.

Then, in February last year, the Colombian Ministry of Health and Social Protection received its first shipment of CoronaVac doses and immediately sent them to towns on the border with Brazil, including Mitu, in order to set up an inoculation blockade to prevent the spread of a worrisome new variant into Colombia.

Authorities provided the vaccine to 99.9 percent of the adult urban population in Mitu, totaling 7,849 people, and Cordoba researchers monitored the effectiveness of the CoronaVac injection.

The results, published this month, revealed a resounding success. CoronaVac showed 99.9 percent effectiveness at preventing severe infection, and just one death was reported. In Mitu, CoronaVac reduced the mortality rate from 2.2 percent in 2020 to 0.22 percent in 2021.

The Colombian health ministry selected CoronaVac for use in remote communities in part because it does not require ultracold refrigeration.

"This vaccination strategy could be relevant to mitigate the spread of COVID-19 in small and remote communities in Latin America," according to the study authors, who were led by University of Cordoba microbiologist Salim Mattar.