The effectiveness rate of the Chinese vaccine in Brazil was announced as 50.38 percent. What is the latest situation in countries that started getting the vaccine ?
important question. In relation to CoronaVac in Brazil, taking into account only a comparison between a proportion of people who developed symptoms between those vaccinated and those who took a placebo, the effectiveness would be 49.6% - below the 50% recommended as the minimum acceptable by the World Health Organization. So depending on the method of evaluating the results, these numbers can vary drastically
You spotted a critical issue. I argue the effectiveness rate is in general acceptable with regard to the vaccines of Moderna and Pfizer-Biontech. The product of Oxford is still under investigation: one cannot say at this point anything certain. The vaccines produced in China and Russia have clearly lower rate of effectiveness. The problem here is that at this moment countries do not have at their disposal enough vaccines and the delivery chains are slow. It can be stated that additional research is needed to find complementary measures for vaccinating:
Lobo-Galo, N., Gálvez-Ruíz, JC., Balderrama-Carmona, A.P. et al. Recent biotechnological advances as potential intervention strategies against COVID-19. 3 Biotech 11, 41 (2021). https://doi.org/10.1007/s13205-020-02619-1
Available at:Article Recent biotechnological advances as potential intervention s...
In addition people around the worlds are not that confident in the ability o COVID-19 vaccines to stop the pandemic:
Mohammad Hossain Shariare et al. (2020). The growing complexity of COVID-19 drug and vaccine candidates: challenges and critical transitions, Journal of Infection and Public Health, 15 December 2020, Article In Press, Open Access: Article The growing complexity of COVID-19 drug and vaccine candidat...
Scientists from the medical center found that the vaccine was 85 percent effective at preventing symptomatic Covid-19 within 15 to 28 days after the shot was administered.