Are Chinese COVID Vaccines Underperforming? A Dearth of Real-Life Studies Leaves Unanswered Questions Analysis 18/06/2021 • Svĕt Lustig Vijay Share this:Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Facebook (Opens in new window)Click to print (Opens in new window) From Indonesia and the Seychelles, to Chile and China itself, there are some worrisome indications that the Chinese Sinopharm and Sinovac COVID vaccines sold by the hundreds of millions to vaccine-strapped low- and middle-income countries may not be performing as well as expected – particularly against rapidly spreading variants of SARS-CoV-2. At the same time, it is too early to draw any conclusions, cautioned WHO’s Chief Scientist, Soumya Swaminathan on Friday – because there is a dearth of well-designed, real-life studies on the massive COVID vaccine rollout underway at either global or national levels. “We need more data, again from well designed studies on the efficacy of the different vaccines that are in use in different countries against the different variants,” said Swaminathan, speaking at a biweekly WHO press conference on Friday. WHO Chief Scientist Soumya Swaminathan She was responding to growing concerns that rapidly advancing vaccination drives are not necessarily leading to the hoped-for sharp reductions in new infections, hospitalizations, and deaths – possibly because some vaccines, including the Sinopharm and Sinovac vaccines from China, are weaker than other frontrunners like Pfizer, Moderna, AstraZeneca, or even Russia’s Sputnik V. Said Swaminathan, WHO has “actually compiled and provided on its website different study designs, to see what happens when people have one dose of the vaccine, two doses of the vaccine”. Such studies would compare COVID illness among those who get vaccines – as compared to those who do not, as the vaccines are rolled out. However, the overwhelming focus of WHO so far, has been getting any approved vaccines to low- and middle-income countries. Comparing how well different vaccine formulations are working once they arrive and get into peoples’ arms has received little attention from the global health agency so far. Spate of COVID Surges In Countries Dependent on Sinovac & Sinopharm Against that background, a spate of recent COVID surges in Latin American and Asian countries that have relied heavily on either the Chinese Sinovac or the Sinopharm vaccines are prompting more questions about the efficacy of those vaccines, in particular. This includes recent reports that over 350 Indonesian healthcare workers who were vaccinated with Sinovac, were reinfected with COVID in mid-June – although only a dozen of those required hospitalization. The Seychelles has seen a significant recent surge of COVID-19 despite almost 70% of the population having been vaccinated, mostly with the Sinopharm vaccine. Of those who were infected, a third reportedly received both shots – but none of them died, according to the country’s health minister. Chile is another country that has scientists scratching their heads. Initially lauded for quickly vaccinating 62% of the population with at least one jab and almost 50% with both jabs, the country went into lockdown last week to contain an outbreak that is triggering 70,000 new cases a day – a caseload that is on par with the heights of the first wave seen last year. About 87% of the vaccines administered in Chile were procured from Sinovac in a deal that is to include procurement of some 60 million doses over three years – making Chile among the largest buyers of Chinese vaccines in Latin America, along with Brazil and Mexico. Together, Latin America and the Asia-Pacific region have bought up some 80% of the 759 million doses of Chinese vaccines sold until now. Most of those doses, about 511 million, were sold by Sinovac, with Sinopharm’s vaccine accounting for the bulk of the remainder of sales so far. Latin America is the second largest buyer of Chinese vaccines after the Asia Pacific region Vaccine Efficacy Ratings For Sinovac And Sinopharm According to the WHO, which recently granted both vaccines “Emergency Use Listings”, Sinovac’s vaccine efficacy stands at 51% against symptomatic disease and 100% against severe disease, while Sinopharm’s efficacy seems to fare slightly better, at 79% against mild and hospitalized disease. But that data fails to include efficacy estimates for older people, one of the main COVID risk groups, as too few took part in large-scale clinical trials. The WHO EUL’s for those two vaccines were unique in that unlike the Pfizer, AstraZeneca, Moderna, and Jonhson & Johonson vaccines that it had also approved, neither had undergone review and approval by a strict national or regional regulatory authority such as the US Food and Drug Administration or the European Medicines Agency. Nor have Phase 3 results of the Sinopharm and Sinovac trials been published in a peer-reviewed medical journal. More to the point, post-approval, any large-scale tracking of the efficacy of the Sinovac and Sinopharm vaccine rollouts by WHO or national authorities seems to be missing. In contrast, rollouts of other vaccines have seen careful monitoring and assessment by the regulatory agencies of the US, UK, Europe, as well as independent researchers. The massive Israeli rollout of Pfizer’s vaccine by countries, for instance, saw the detailed reporting of data on illness, hospitalizations, and among hundreds of thousands of people who were vaccinated as compared to similar groups of people who had not received their jabs. The massive tracking of outcomes, including peer reviewed publication of results, helped boost confidence in the mRNA vaccines. But outside of developed countries, such tracking appears to be much weaker – or non-existent. One exception is a report by the Uruguayan government this week on a study of some 800,000 people who received two Sinovac vaccine shots – representing some 35% of the population. The study, which so far has not been published in a peer-reviewed journal, concluded that deaths among people immunized with the Sinovac vaccine had been cut by 95%, intensive care admissions by 92% and infections by 61%. At the same time, Uruguay has also recently seen one of the largest COVID spikes in the world – with over 766 cases per million on 17 June, as compared to 50 per million in India and just 36 in the United States on the same day. Complex Factors At Work The lack of hard data on the efficacy of different vaccines being used in large scale rollouts has left WHO – as well as other health experts – to respond anecdotally. Dr Bruce Aylward, Senior Advisor to the WHO Director General For instance, with regards to the reinfection of Indonesian health workers with COVID-19, WHO Senior Advisor to the Director-General Bruce Alyward noted that this is not necessarily unexpected, especially during intense periods of community transmission. “There are reports of people who received Sinovac [who] caught the disease, the health care workers,” Aylward acknowledged, referring to the Indonesian reinfection case. “But that does not mean failure of the vaccine because as you know, vaccines are not going to protect everybody who receives them,” he explained. “The vaccine efficacy estimate [for Sinovac] is between 50% to 76%…it’s not unexpected in areas where everyone gets a vaccine as we get intense transmission, there will be some [COVID] cases in people who are vaccinated.” Although Sinovac’s weaker efficacy rating may have contributed to Chile’s current outbreak, Ian Jones, Professor of Virology at the University of Reading in the UK, contended that the nation’s complacency also has a role to play: “In Chile, it seems clear that there was a sense of success after only part of the population had been immunised with the inactivated vaccine,” he told Health Policy Watch: “That led to a false sense of security as the single dose only provided about 55% protection and, in addition, many people remained unvaccinated and naive. The opening up allowed ample mixing and the case rate took off again – even if those vaccinated were protected from severe infection.” Antoine Flahault, Director of the Global Health Institute at the University of Geneva, added that we should also “keep in mind that these Latin American countries are entering their cold season”, which favors the spread of respiratory viruses like SARS-CoV-2. WHO’s Swaminathan has also cautioned that more documentation is needed to shed light on whether people who are vaccinated still contract milder, or more severe forms of the disease, and to what extent. “If there’s a lot of community transmission there will be more infection among health workers, but are they getting ill, are they needing to be hospitalised and what’s the proportion between the vaccinated, unvaccinated and those with a single dose and complete doses?” said Swaminathan. “I think we have to be very careful about suggesting there’s evidence that a vaccine is failing because there certainly isn’t the evidence to suggest that at this point.” Data On Vaccine Efficacy Against Variants “Limited” To “Very Limited” People waiting to register for the Sinopharm vaccine at the Pakistan Institute of Medical Science. WHO’s Weekly Epidemiological Update from 8 June acknowledged that the evidence around vaccine efficacy against variants remains “limited” to “very limited” – adding that the vaccines still are “likely” to confer some degree of protection against COVID-19 disease. Those variants of concern include Alpha, first discovered in the UK, Beta (South Africa), Gamma (Brazil), and Delta (India). All of those have now been identified in the Latin American context, notably in Chile and Brazil. The Epidemiological update from early June cites a number of studies suggesting that the Beta and Gamma variants, in particular, appear to lead to “minimal-to-modest” reductions in neutralization capacity of Sinopharm and Sinovac vaccines; although the alpha variant appears to lead to “no/minimal loss” in neutralization capacity in both cases. Experts have meanwhile warned that studies of vaccine performance against new variants are limited mainly to small populations or laboratory analyses of the so-called “neutralizing antibodies” found in blood samples – as compared to real-life epidemiological surveys. WHO has also highlighted that all vaccines, including the most efficacious mRNA vaccines, perform less well against new variants. It cites, as an example, one study from Qatar, which found the Pfizer vaccine to be less effective against symptomatic diseases against Alpha and Beta variants – although not necessarily for hospitalizations and deaths. On the other hand, studies from Israel, where some 53% of the population was vaccinated with the Pfizer mRNA vaccine, have confirmed the high protection the mRNA vaccines appear to confer against the alpha variant, at least. Weak Chinese Vaccines Could Deal COVAX & Latin America Big Blow If the two Chinese vaccines turn out to perform poorly in real-life contexts, it could deal the vaccine-thirsty COVAX facility a large blow. The Facility, led by Gavi, the Vaccine Alliance and WHO plans to seal deals with Sinopharm and Sinovac on large-scale procurement of the vaccines for developing countries – in the wake of WHO’s recent decision to grant both vaccines an Emergency Use Listing. If more problems emerge, it also would be particularly unfortunate for Latin America, which is currently seeing higher rates of COVID transmission than most regions in the world – including India. Latin America has so far procured 289 million of the 759 million doses of Chinese vaccines produced so far. As such, it is the second largest regional buyer of Chinese vaccines after the Asian Pacific region, according to the China Vaccine Tracker – a joint initiative by the Beijing-based Bridge Consulting and New York-based Global Health Strategies. China has already delivered 272 million doses to at least 40 countries ‘Literally Everyone Needs to be Vaccinated’ Even if the Chinese vaccines are efficacious against severe disease and death, they may be less effective in halting transmission of SARS-CoV-2. That could explain some of the spikes being seen now in Latin America, Beate Kampmann, Director of The Vaccine Centre at the London School of Hygiene and Tropical Medicine, told Health Policy Watch. She added, however, that “the only way to be certain is to conduct nasal carriage studies of Sars-CoV2 to show if viral load remains high/virus present in vaccinated people” – adding that no such studies have been done for the Sinopharm and Sinovac vaccines. In contrast, multiple studies undertaken on Pfizer as well as AstraZeneca vaccines have shown they significantly cut SARS-CoV-2 transmission. If this is indeed the case, then a much larger proportion of the population will have to be vaccinated with the Chinese vaccines to really curb local transmissions, she warned. “As far as transmission is concerned, these [Chinese] vaccines are not going to be helpful unless literally everyone is vaccinated,” said Kampmann. “And even then, the virus would still circulate and subsequent cohorts need to be protected via vaccination as well.” -Elaine Ruth Fletcher contributed to this story. Image Credits: Twitter – Chinese Ambassador to Zimbabwe, Bridge Consulting, Rahul Basharat Rajput. 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