Covid-19 vaccines from Chinese companies Sinopharm (left) and Sinovac arrived at Phnom Penh International Airport in Cambodia on June 8, 2021.
Sovannara | Xinhua News Agency | Getty Images
Among the countries with both high vaccination rates and high Covid-19 infection rates, most rely on vaccines made in China, a CNBC analysis shows.
The results come as the effectiveness of Chinese vaccines comes under increasing scrutiny, compounded by a lack of data on their protection against the more transmissible Delta variant. CNBC found that weekly population-adjusted Covid cases have remained elevated in at least six of the world’s most heavily vaccinated countries – and five of them rely on vaccines from China.
CNBC identified 36 countries with more than 1,000 weekly new confirmed cases per million people on July 6, using figures from Our World in Data, which compiles information from sources such as the World Health Organization, governments and Oxford University researchers. CNBC then identified countries among those 36 where more than 60% of the population had received at least one dose of the Covid vaccine.
There were six countries, and five of them use Chinese vaccines as an essential part of their national vaccination programs: United Arab Emirates, Seychelles, Mongolia, Uruguay, and Chile. The only country among them that does not rely on Chinese vaccines is the United Kingdom.
The UK has now approved vaccines from Moderna, AstraZeneca-Oxford, Pfizer-BioNTech and Janssen. Covid cases in the UK have increased in recent weeks as the more transmissible Delta variant has spread there.
Sinopharm and Sinovac did not respond to CNBC requests for comment.
Several factors can lead to an increase in Covid cases in countries with high vaccination rates. Vaccines do not offer one hundred percent protection, so those who are vaccinated can still get infected. At the same time, new variants of the coronavirus might prove better at overcoming vaccines.
The best option for many countries
Still, countries shouldn’t stop using Covid-19 vaccines from China, epidemiologists say, especially when vaccine supplies are limited in low- and middle-income countries.
Many of the countries and territories that have approved Sinopharm and Sinovac vaccines are developing countries that cannot compete with wealthier countries for vaccines developed in the United States and Europe.
Ben Cowling, a professor in the University of Hong Kong’s School of Public Health, said countries could choose to use certain vaccines depending on their long-term goals.
“Some countries may accept low prevalence as long as there are relatively few serious cases and deaths from COVID-19,” Cowling, who heads the school’s epidemiology and biostatistics department, told CNBC in an email. “That should be achievable with a high coverage of all available vaccines.”
However, some countries avoid vaccines in China. Costa Rica turned down shipments of vaccines developed by Sinovac last month after it concluded they were not effective enough.
The World Health Organization has approved Sinopharm and Sinovac vaccines for emergency use.
The two Chinese vaccines are less effective than Pfizer-BioNTech and Moderna, both of which have shown greater than 90% effectiveness.
Sinopharm’s vaccine is 79% effective against symptomatic Covid infections, the WHO says, but its effectiveness in certain groups – such as people over 60 – is not clear. The effectiveness of Sinovac’s shot ranges from around 50% to over 80%, depending on the country in which the trials took place.
Experts say that the results cannot be directly compared between clinical trials because each study is structured differently. However, a study in Hong Kong found “significantly higher” antibody levels in people who received the BioNTech injection compared to those who received the Sinovac vaccine, the South China Morning Post reported.
Some experts suggest that the technology behind the various Covid vaccines could explain differences in their effectiveness.
Sinopharm and Sinovac vaccines trigger an immune response by exposing the body to a weakened or “inactivated” virus – a proven method that vaccines have used for decades. Pfizer-BioNTech and Moderna based their vaccines on a technology called messenger RNA, which instructs the body to make viral proteins that trigger an immune response.
“Inactivated vaccines are easy to make and are known for their safety, but tend to have a weaker immune response compared to some other vaccine types,” wrote Michael Head, Senior Research Fellow on Global Health at the University of Southampton in the UK, in an article, published on The Conversation website.
Still, large phase three clinical trials showed that inactivated vaccines were “highly effective against serious illness and death” from Covid, Cowling said.
The professor told CNBC that the spikes in Covid cases in some countries using Chinese vaccines “are typically an increase in mild infections with very few severe cases in fully vaccinated people”.
When vaccines are less effective, more people need to be vaccinated to achieve “herd immunity”. This happens when the virus stops being transmitted quickly because most people are immune to a vaccination or have recovered from an infection.
Some countries decided to try to achieve herd immunity at the beginning of the pandemic, but are not known to have succeeded. Some who said they would achieve herd immunity, like Sweden, have been hit much harder by Covid than neighboring countries that have taken the vaccination route.
A study by the Kirby Institute at the University of New South Wales in Sydney claimed that in the Australian state of New South Wales, herd immunity could be achieved if 66% of the population were given vaccines that were 90% effective against all infections.
The percentage of the population who needs to be vaccinated increases to 86% when vaccine effectiveness is 70%, and herd immunity is not achievable when vaccine effectiveness is below 60%, the study showed.