The COVID-19 vaccine made by China's Sinopharm was less effective than others at preventing infection, hospitalisation and death, according to a new study.

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A report published by The Wall Street Journal stated that this study, conducted by the kingdom of Bahrain and Columbia University researchers, especially holds true among people over 50. This comes as Chinese vaccines have become a major factor in Beijing's diplomacy manoeuvres, especially in developing countries with fewer resources.

The WSJ report stated that despite high levels of inoculation with the Sinopharm vaccine, Bahrain in May started giving booster shots to vulnerable citizens using a different shot made by Pfizer Inc. and BioNTech SE. "It now also offers booster shots for other vaccines," the report added.

According to the study, all the vaccines administered since December in Bahrain--which also include Covishield, and the Russian-made Sputnik V--were effective in combatting the virus compared to the unvaccinated population. Dr Jaleela Al-Sayed Jawad, co-author of the study said researchers found that there is a "significant difference" between hospitalisation, ICU admission and death in favour of Pfizer compared to Sinopharm, especially in older populations. The study also stands true in the context of the emergence of the Delta variant.

Last month, reports had emerged that China plans to use an mRNA vaccine, co-developed by China's Fosun Pharma and Germany's BioNTech, as a booster shot for those already vaccinated in the country using other Chinese vaccines.

Despite giving over 1 billion doses of COVID-19 vaccine, it has no plans to relax its border restrictions until at least 2022, The Diplomat reported. Most of the citizens have received vaccines made by Sinovac and Sinopharm Group. Both these vaccines use inactivated particles of the virus, rather than the newer mRNA technology. "Chinese authorities plan to use the vaccine, which goes by the brand name Comirnaty, as a booster shot for people who have received inactivated-virus vaccines, people close to regulators told Caixin," according to The Diplomat's report citing Chinese media outlet Caixin.