Covid-19 vaccines from Chinese companies Sinopharm (left) and Sinovac arrived at Phnom Penh International Airport in Cambodia on June 8, 2021.
Sovannara | Xinhua Press Agency | Getty Images
Of the countries with both high vaccination coverage and high rates of Covid-19 infection, most rely on vaccines made in China, a The Washington City Times analysis shows.
The findings come as the efficacy of Chinese vaccines comes under increasing scrutiny, compounded by a lack of data on their protection against the more transmissible delta variant. The Washington City Times found that weekly population-adjusted Covid cases have remained elevated in at least six of the world’s most inoculated countries — and five of those rely on vaccines from China.
The Washington City Times identified 36 countries with more than 1,000 weekly new confirmed cases per million people as of July 6, using figures from Our World in Data, which compiles information from sources including the World Health Organization, governments and researchers at the University of Oxford. The Washington City Times then identified among those 36 countries where more than 60% of the population has received at least one dose of Covid vaccine.
There were six, and five of them are using Chinese vaccines as an important 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 United Kingdom has now approved vaccines from Moderna, AstraZeneca-Oxford, Pfizer-BioNTech and Janssen. The number of Covid cases in the UK has risen sharply in recent weeks as the more transmissible delta variant has spread there.
Sinopharm and Sinovac did not respond to The Washington City Times’s requests for comment.
Several factors can cause an increase in Covid cases in countries with high vaccination rates. Vaccines do not provide 100% protection, so those who have been vaccinated can still be infected. At the same time, new variants of the coronavirus may prove to be better at overcoming vaccines.
The best option for many countries
Countries should not stop using Covid-19 vaccines from China, epidemiologists say, especially now that vaccine supply is limited among low- and middle-income countries.
Many of the countries and territories that have approved vaccines from Sinopharm and Sinovac are developing countries that cannot compete with wealthier countries for vaccines developed in the United States and Europe.
Ben Cowling, a professor at the University of Hong Kong’s School of Public Health, said countries can decide to use certain vaccines depending on their long-term goals.
“Some countries will accept low levels of circulation as long as there are relatively few severe cases and deaths from COVID-19,” Cowling, chief of the school’s department of epidemiology and biostatistics, told The Washington City Times in an email. “That should be achievable with high coverage of any of the available vaccines.”
Still, some countries steer clear of Chinese vaccines. Costa Rica rejected a supply of vaccines developed by Sinovac last month after it concluded it was not effective enough.
The World Health Organization approved vaccines from Sinopharm and Sinovac for emergency use.
The effectiveness of the two Chinese vaccines is lower than that of Pfizer-BioNTech and Moderna, both of which have shown efficacy of over 90%.
Sinopharm’s vaccine has 79% efficacy against symptomatic Covid infections, the WHO says, but its effectiveness in certain groups – such as people aged 60 and older – is not clear. The efficacy of Sinovac’s injection has ranged from around 50% to over 80%, depending on the country where the trials were conducted.
Experts say findings cannot be directly compared between clinical trials because each trial is designed differently. But a study in Hong Kong found “significantly higher” antibody levels in people who received the BioNTech injection, compared with those who received the Sinovac vaccine, the South China Morning Post reported.
Some experts suggest that the technology behind the different Covid vaccines could explain variations in their effectiveness.
Sinopharm and Sinovac’s vaccines trigger an immune response by exposing the body to a weakened or “inactivated” virus – a proven method that has been used by vaccines for decades. Pfizer-BioNTech and Moderna based their vaccines on a technology called messenger RNA, which instructs the body to make viral proteins that elicit an immune response.
“Inactivated vaccines are easy to manufacture and known for their safety, but tend to produce a weaker immune response compared to some other vaccine types,” wrote Michael Head, senior research fellow in global health at the University of Southampton in the UK, in an article published on The Conversation website.
Still, large clinical phase three clinical trials showed that inactivated vaccines have “high efficacy against severe illness and death” from Covid, Cowling said.
The professor told The Washington City Times that the spikes in Covid cases in some countries using Chinese vaccines are “usually an increase in mild infections with very few severe cases in fully vaccinated individuals.”
When vaccines have lower efficacy, more people need to be vaccinated to achieve ‘herd immunity’. That happens when the virus no longer passes quickly, because most people are immune to vaccination or recover from an infection.
Some countries have decided to try to achieve herd immunity early in the pandemic, but no countries are known to have succeeded. Some who said they would achieve herd immunity, such as Sweden, ended up being much harder hit by Covid than neighboring countries following 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 received vaccines with 90% efficacy against all infections. .
The proportion of the population that should be vaccinated rises to 86% if vaccine effectiveness is 70%, and herd immunity is not feasible if vaccine effectiveness is below 60%, the study found.