The World Health Organization (WHO) is considering approving two of China’s COVID-19 vaccines for emergency use, potentially opening the door to wide distribution in lower-income nations through the COVID-19 Vaccines Global Access (COVAX) initiative.
A successful outcome in coming weeks might boost global confidence in these vaccines, say scientists. China’s five different vaccines have not been used widely in wealthy nations, but are already sustaining immunization campaigns in the global south.
“There is big demand for the Chinese vaccines,” says Firdausi Qadri, an immunologist at the International Centre for Diarrhoeal Disease Research, Bangladesh, in Dhaka.
One of the two vaccines under review is made in Beijing by Chinese state-owned firm Sinopharm. The other — named CoronaVac — is produced by private company Sinovac, also based in Beijing. If listed, they will join five COVID-19 vaccines already authorized by the WHO, but will be the first to use inactivated virus and the only ones not widely used in Western nations.
Sinopharm and Sinovac’s vaccines account for the bulk of shots given in China, which has so far inoculated 243 million people. More than 45 countries have already approved their use, but the WHO is among the first stringent regulatory authorities to review the data.
“It is very important to have the support of the WHO,” says Rafael Araos, a physician and epidemiologist at University for Development in Santiago, Chile. A positive response will be “very good news for the vaccine developers and for the countries that are interested in getting these vaccines.”
Addressing the shortfall
The WHO approval process assesses safety, efficacy and manufacturing quality, says Qadri. Approved products can be purchased by United Nations agencies. “Until that happens, it will be up to the individual countries to procure the vaccines, and most countries will be not be able to,” she adds.
The vaccines could also help to address the current shortfall in vaccines available through COVAX, an initiative led by international partnerships and agencies, including the WHO, to ensure that COVID-19 vaccines are distributed equitably.
COVAX has so far shipped only about 50 million of the 2 billion doses it aims to deliver globally in 2021. India is meant to contribute one billion doses of its Covishield vaccine, but exports have halted, owing to the country’s ongoing COVID-19 crisis. Deliveries to COVAX of another WHO-listed vaccine produced by the pharmaceutical firm Pfizer have been limited and none of Johnson & Johnson’s have been shipped yet. Moderna’s vaccine was listed by the WHO on 30 April.
As a result, Chinese vaccines are badly needed, says Gagandeep Kang, a virologist at the Christian Medical College in Vellore, India, and a member of a technical group on immunization that advises the WHO. The group met on 29 April to review data on the two Chinese vaccines, and will soon provide recommendations on their use.
Inactivated-virus vaccines have generally proven less effective than others in use. However, they still exceed the WHO’s 50% efficacy threshold for emergency-use approval, making them important to reduce the global shortfall, argues Murat Akova, a clinical infectious-diseases researcher at Hacettepe University in Ankara, Turkey. “If nothing else is available, I think these vaccines are a good choice.”
Chinese researchers were among the first to begin developing vaccines against COVID-19 in early 2020, but they have yet to publish full trial results. Some researchers have raised concerns that a lack of transparency could fuel vaccine hesitancy, but others say collating the data takes time and resources, and should be available for both front-runner vaccines within weeks.
China’s vaccines (see ‘How China’s vaccines compare’) have had to be trialled elsewhere because the country didn’t have enough transmission itself to conduct them, says George Gao, who heads the Chinese Center for Disease Control and Prevention, in Beijing.
So far, only scattered information from various nations has been released on Sinopharm’s Beijing vaccine, says Hilda Bastian, an independent scientist who studies evidence-based medicine in Victoria, Australia (Sinopharm is producing a second inactivated-virus vaccine in Wuhan). She hopes the WHO will now release detailed data.
In early December, both the United Arab Emirates (UAE) and Bahrain approved it — making it among the first COVID-19 vaccines to be granted full clearance in any country. Approval was based on late-stage trial data, including a UAE study involving 31,000 participants. These showed the vaccine was 86% effective at preventing COVID-19 after 2 shots, with no deaths among immunized individuals. Documents published following the 29 April meeting suggest the combined trial efficacy over several countries was 78%.
Data on CoronaVac from clinical trials and national vaccination campaigns have also emerged, with mixed results. Trials from Brazil and Turkey have revealed efficacy figures of 50.7% and 83.5%, respectively. Researchers say the lower figure might be because Brazil includes mild cases of COVID-19 in its counting and because there is circulation of the P.1 variant, which is more transmissible and might be better at evading immunity. Results from an analysis following mass vaccinations in Chile have landed between these numbers, at 67%.
China’s vaccine drive
The CoronaVac and both Sinopharm vaccines are the mainstay of China’s own immunization drive, which aims to vaccinate 70% of its population of 1.4 billion by the end of 2021. China approved its first COVID-19 vaccines for emergency use in June 2020 and began rolling out doses more widely in January.
So far, only Chinese vaccines have been listed by the country’s drug agency, which since December has approved both Sinopharm’s vaccines; CoronaVac; and a fourth vaccine produced by CanSino Biologics in Tianjin, which uses an adenovirus to introduce DNA encoding the SARS-CoV-2 spike protein into human cells.
Last month, China’s drug agency also gave emergency-use authorization to a vaccine produced by Anhui Zhifei Longcom, a firm based in Hefei. It works by introducing part of the virus’s receptor-binding domain protein to human cells and is now undergoing phase III trials in Uzbekistan.
Gao says the Chinese vaccines generally provide good protection, but might need subsequent boosters to induce stronger protection. Mixing vaccines that use different technologies or different modes of entry, such as nasal sprays, might be useful, he adds.
China’s vaccines have already catalysed immunization campaigns in more than 40 countries. The country aims to produce between three and five billion doses this year, and more may come from manufacturing deals with other countries, such as the UAE, which is making a version of Sinopharm’s Beijing vaccine, called Hayat-Vax.
For many countries, Chinese vaccines were the only accessible ones. In others — such as Brazil, Turkey and Chile, where many tens of millions of people have been vaccinated — they make up some 80-90% of doses administered. And researchers in these countries are beginning to see evidence of their effect in controlling the pandemic1.
Anecdotal reports hint at a low incidence of breakthrough infections, severe illness and death among fully vaccinated individuals in Brazil, says Esper Kallas, an infectious-diseases researcher at the University of São Paulo, Brazil. “Because we have access to CoronaVac, we’ve got to use it”, he says. “I’m not saying this will be the preferred vaccine in the future.”
WHO’s emergency-use listing of CoronaVac would further validate its use in countries that led with it. The decision to approve it would “provide confidence”, says Akova.
But many questions remain about the vaccines. Researchers want more data on how well they protect older people, children, pregnant women and immunocompromised groups. They also want to know what types of immune response the jabs trigger, how long protection lasts and how well they work against emerging variants. “The more data we have, the better,” says Kallas.