On Friday, the WHO listed China-made Sinopharm COVID-19 vaccine for emergency use, implying that the vaccine can now be used in immunisation drives worldwide. The vaccine is produced by the Beijing Bio-Institute of Biological Products Co Ltd, which is a subsidiary of China National Biotec Group (CNBG).
Sinopharm is the first non-Western vaccine to get WHO backing and will possibly be used for the COVAX programme, under which vaccines are supplied to low and middle-income countries. India, which had exported vaccines manufactured at the Serum Institute of India (SII) under the COVAX programme earlier this year, stopped exports in mid-March to meet its domestic demand as coronavirus cases started surging towards the end of February.
How does this vaccine work?
The Sinopharm vaccine is an inactivated coronavirus vaccine, like Covaxin developed by Bharat Biotech India (BBIL) in collaboration with the National Institute of Virology (NIV).
Inactivated vaccines take the disease-carrying virus (in this case SARS-CoV-2) and kill it using heat, chemicals or radiation. WHO notes that these vaccines take longer to make and might need two or three doses to be administered. The flu and polio vaccines use this approach as well.
Out of the major vaccines being used in the world, Sinopharm, Covaxin and Sinovac (also developed by China) are the only ones that use inactivated virus. Others such as Pfizer-BioNTech and Moderna are mRNA vaccines, whereas Oxford-AstraZeneca, Sputnik and Johnson and Johnson’s single-dose vaccines use a viral vector.
As per WHO, Sinopharm has an efficacy of about 79 percent for symptomatic and hospitalised disease for all age groups. However it notes that since few adults over the age of 60 years were enrolled, the efficacy in the age group is not clear.
Even so, the WHO has not recommended an upper age limit on the use of this vaccine “because preliminary data and supportive immunogenicity data suggest the vaccine is likely to have a protective effect in older persons. There is no theoretical reason to believe that the vaccine has a different safety profile in older and younger populations.”
As of now the WHO has recommended that the vaccine be administered to adults of the age of 18 and above in a two-dose schedule with a gap of three to four weeks.