The approved two-shot vaccines are generally more effective, but experts have warned not to compare the efficacy of vaccines.
The World Health Organization (WHO) has approved six vaccines for emergency use. The list includes one single-shot vaccine. Pfizer/BioNTech, Astrazeneca-Oxford (Covishield), Janssen, Moderna, Sinovac, and Sinopharm have all been signed off for emergency use. In March 2021, WHO approved the use of a single-shot vaccine developed by Janssen (Johnson & Johnson (J&J) . According to CDC, the J&J vaccine has shown efficacy of 66.3per cent in clinical trials. Meanwhile, the single-shot Sinopharm vaccine developed by the China National Biotec Group (CNBG), and another manufactured by Moderna, have an efficacy rate of 79 percent and 92 percent against symptomatic COVID-19 infection respectively. The efficacy of Sinopharm against hospitalization was 79 percent. The vaccine developed by Beijing-based pharmaceutical company Sinovac was recommended for use in adults aged 18 and above. The vaccine would give 100 percent prevention against the hospitalization of COVID-19 patients and 51 percent efficacy against the symptomatic infection. On December 31, 2020, WHO has listed the Pfizer vaccine for emergency usage. According to the CDC, trials resulted in an efficiency of 95 percent in confirmed COVID-19 cases. It also mentioned that the vaccine had prevented the infection in people aged between 12-15. WHO has listed two versions of the Covishield vaccine developed by AstraZeneca/Oxford in February 2021. It was mentioned that the vaccine is 63.09 percent effective against the COVID-19 virus and can store easily. The Sputnik light vaccine is a single-shot vaccine developed by the bio firm Sputnik V. The vaccine has only been authorized for use in Russia. Sputnik's vaccine developers have claimed that their single-shot vaccine has "An efficacy level almost 80 percent higher than that of many two-dose vaccines."It declared that after 28 days of getting the single-shot Sputnik Light vaccine, 96.96 percent of individuals would develop antigen-specific IgG antibodies in their bodies." However, as noted in the Associated Press, healthcare experts, including the FDA's Dr. Jesse Goodman, have emphasized that it would not be fair to compare the overall efficacies of these vaccines as the COVID-19 virus is mutating and changing, and the vaccines' capabilities are constantly being evaluated. The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19 including symptoms, prevention and available treatment, please refer to the World Health Organisation or your national healthcare authority. The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19, including symptoms, prevention, and available treatment, please refer to the World Health Organization or your national healthcare authority.