Despite a sluggish start, China is now vaccinating its people against COVID-19 at an impressive clip, currently averaging nearly 20 million doses administered per day. As of Friday, the country had given more than 720 million vaccinations since mid-December, with nearly 400 million of those were given in May alone.

The dramatic ramp up comes at an awkward time, however. Early adopters of China’s vaccines have seen dramatic surges in COVID-19 cases—despite high vaccination rates—and are now backing away from the country’s offerings.

In Bahrain, for instance, officials are now offering high-risk people who have already received two doses of China’s Sinopharm vaccine a third vaccine dose—but one made by Pfizer-BioNTech. The apparent vote of no confidence by officials is striking: Bahrain was one of the first countries to back and rollout Sinopharm’s vaccine, and it has had a highly successful vaccination campaign. Nearly 58 percent of the Persian Gulf country has received at least one dose of a vaccine, and most of the vaccines given in Bahrain are from Sinopharm. But the country is now seeing its worst wave of COVID-19 yet and the government has recently issued a two-week lockdown to try to get transmission under control.

The Seychelles went through a similar struggle. The archipelago saw a dramatic spike in cases in mid-May, despite having around 70 percent of its population vaccinated with at least one dose. Like Bahrain, the Seychelles had largely relied on the Sinopharm vaccine.

Dubai, which has also relied on Sinopharm’s vaccine, is now quietly offering residents who have been fully vaccinated with the Sinopharm vaccine the opportunity to get re-vaccinated with the Pfizer-BioNTech vaccine, according to The Wall Street Journal.

Efficacy “not high”

In a study published on May 26 in JAMA, Sinopharm researchers reported results suggesting that their inactivated virus vaccine was up to 78 percent effective against symptomatic COVID-19 cases. But the study was done mainly in young, healthy men, and the results were not conclusive regarding whether the vaccine was effective against severe disease or asymptomatic cases.

Unpublished data out of Serbia suggested that some people given the vaccine may not produce antibodies to fight off the pandemic coronavirus three months after vaccination, according to reporting by the Wall Street Journal. “The Sinopharm vaccine is not immunogenic enough, and it appears that its impact is especially low on elderly recipients,” said Olgica Djurkovic-Djakovic, of the University of Belgrade, who led the unpublished study and shared the findings with the Journal.

In April, the head of China’s Centers for Disease Control and Prevention, George Gao, seemed to acknowledge this potential problem. “The efficacy of the existing vaccines is not high,” he said at a conference, discussing the country’s vaccines. Last month, Beijing reportedly began planning to offer third doses of the country’s vaccines to try to boost protection.

Still, last month the World Health Organization granted an emergency use listing (EUL) for Sinopharm’s COVID-19 vaccine, paving its way for global use. Just on Tuesday, the WHO granted an EUL to China’s Sinovac vaccine. Like Sinopharm’s vaccine, Sinovac’s vaccine is an inactivated virus vaccine, and the two appear to have similar track records. Both Chile and Uruguay rolled Sinovac’s vaccine into their mass vaccination campaigns and have seen subsequent spikes in cases.

https://arstechnica.com/?p=1770201