In western countries, attention has understandably focused on which of the western-made COVID-19 vaccines people are likely to receive. But globally, these are far from the only products available. China, for instance, has developed multiple COVID-19 vaccines, and these are now being used to protect people both domestically and abroad.
One of these is the vaccine developed by Sinopharm, a Chinese state-owned company. It’s been authorised for use in over 50 countries, with tens of millions of doses having been given worldwide. Over 100 million doses have been ordered from outside China, the result being that the product forms a major part of vaccination programmes in many countries.
The World Health Organization (WHO) has issued an interim recommendation that the vaccine be used, stating that it’s sufficiently safe and effective. Yet COVID-19 cases have risen in some countries using the Sinopharm jab, and there have been reports of vaccinated people getting infected. With so many relying on the vaccine, is this a cause for alarm?
How it works
The Sinopharm jab is an inactivated vaccine, containing a killed coronavirus that cannot replicate. This is a different approach to the mRNA-based vaccines of Pfizer and Moderna and the viral-vectored platforms used by the Oxford/AstraZeneca, Sputnik V and Johnson & Johnson vaccines.
Using a whole, inactivated version of a virus to stimulate an immune response is tried and tested – historically many vaccines have used this approach. Examples include those for rabies and polio. Inactivated vaccines are easy to manufacture and are known for their safety, but tend to produce a weaker immune response compared to some other vaccine types.
The WHO initially reported that trials showed the vaccine to be 79% protective against both symptomatic disease and hospitalisation after two doses. Real-world evidence suggests protection against both symptomatic and severe COVID-19 could be higher still: possibly as high as 90%.
But the picture isn’t quite clear cut. With the Pfizer, Moderna and AstraZeneca vaccines, there’s lots of data on their performance. But with the Sinopharm vaccine, we don’t have as much performance data to look at, so we can’t be as certain of its efficacy, even if its numbers look good. The director of the Chinese Center for Disease Control and Prevention, Gao Fu, has also publicly said the Chinese-developed products needed improving.
There’s certainly a lack of data on how effective the Sinopharm vaccine is against variants of concern. Information available suggests it still works against the beta variant (B1351, first observed in South Africa), but may be less effective, though this was a small, lab-based study. Little is known about levels of protection against other variants. This gives some cause for concern.
Outbreaks should be expected
There have recently been outbreaks in a number of countries with relatively advanced vaccination programmes, including those that are and aren’t using the Sinopharm vaccine. Cases have risen in the UK, for example, as the delta variant has become dominant there. It isn’t using the Sinopharm vaccine.
However, increases in COVID-19 cases do appear to have been particularly apparent in countries using the Sinopharm jab. The Seychelles witnessed a notable spike, despite (at the time of reporting) over 60% of the country having had two doses. The initial vaccine used in the Seychelles was Sinopharm’s, along with additional use of AstraZeneca’s. It was reported that around one-third of new cases were in fully vaccinated people. Similar scenarios have been seen elsewhere, including in Chile, Bahrain and Uruguay.
There are several reasons why we might see new cases in fully vaccinated individuals. Firstly, none of the vaccines are 100% effective (and Sinopharm’s appears to probably be significantly less than that). Variants of concern can also lower protection. The immune response also takes a few weeks to fully develop. Some people may have been infected soon after their second dose.
What we have seen is that cases in vaccinated people are typically milder than in unvaccinated people, and that vaccines do appear to reduce transmission. Vaccines are, and will remain, the key tool that underpins the global route out of the pandemic. Therefore, we shouldn’t think of these events as “vaccine failures”, but as the impact of their limitations. These impacts may be more visible when using a less protective vaccine like Sinopharm’s compared to one such as Pfizer’s. This could explain why outbreaks have been more noticeable in countries using the Sinopharm vaccine widely.
Ultimately, if susceptible populations mix with infectious individuals, then there may be some onward transmission, no matter the vaccine.
A mixed solution
Countries are responding to outbreaks by scaling up and enhancing their existing rollouts, but also sometimes by offering booster doses of other vaccines. Bahrain and the United Arab Emirates have recommended an additional Sinopharm dose, or a single dose of Pfizer, around six months after someone has received two doses of Sinopharm. This will likely boost overall levels of protection, but is very much dependent upon countries having sufficient supply.
While vaccine demand outstrips supply and high-income nations hoard much of what is produced, the majority of the world remains unprotected and susceptible to COVID-19. Any further uncontrolled outbreaks, such as we have seen in India and other countries such as Nepal, not only risk overburdening fragile health systems in lower-income areas, but also facilitate further chances for new variants to emerge.
With this in mind, we should remember that the Sinopharm vaccine is a useful product. Other vaccines may well provide better protection – we’ll get a better sense of exactly how good the Sinopharm vaccine is as more data emerges – but China will undoubtedly continue to be able to supply many doses to the world. The Sinopharm jab will therefore be one of the tools that underpins the global response over the next 12-24 months.
Michael Head has received funding from the Bill & Melinda Gates Foundation and the UK Department for International Development.