With surging COVID-19 cases the world is now waiting for a vaccine to stop the spread of the disease which has killed millions worldwide.
When candidate vaccines make it to human clinical trials, they first go through Phase 1 trials to test the vaccine’s safety, determine dosages and identify any potential side effects in a small number of people.
Phase 2 trials include exploring the safety and starting an investigation on efficacy by testing it on larger groups.
The Phase 3 trials are much larger and longer and it involves thousands or tens of thousands of people, to confirm and assess the effectiveness of the vaccine and test whether there are any rare side effects that only show up in large groups. The World Health Organization lists candidates at various stages of clinical trials.
At present several candidates are trying their luck in the phase three trials of COVID-19 vaccine. We have listed down the efficiencies of those vaccines.
1. AZD1222: The University of Oxford, AstraZeneca, IQVIA and Serum Institute of India
Its combined analysis has an average efficacy of 70 percent.
One dosing regimen shows a vaccine efficacy of 90 percent when AZD1222 was given as half dose, followed by a full dose at least a month apart. Second dosing regimen shows 62 percent efficacy when given two full doses at least a month apart.
2. BNT162: Pfizer-BioNTech coronavirus vaccine
Pfizer vaccine has shown 95 percent efficacy in a totality of two data sets released recently. According to Pfizer data, of the 170 volunteers who contracted Covid-19 during Phase III trials involving over 43,000 people, 162 had received a placebo and only eight received the two-dose vaccine which shows that the vaccine was 95 percent effective.
3.mRNA-1273: Moderna coronavirus vaccine
The US pharma giant last week said that its vaccine has shown more than 94.5 per cent effectiveness in preliminary data from the company's ongoing study, raising hope delivering a potent weapon to beat the pandemic.
By the end of 2020, Moderna expects to produce approximately 20 million doses of its mRNA-1273 vaccine.
4. Covaxin: Bharat Biotech; National Institute of Virology
As per the firm’s statement, trials conducted thus far suggest its vaccine candidate 'Covaxin' will be at least 60 percent effective. With the minimum criteria set, the company was now attempting to reach an even higher success rate. “Chances of the vaccine being less than 50 percent effective are remote," it added.
5. Sputnik V: Gamaleya Research Institute, Acellena Contract Drug Research and Development
The Sputnik V vaccine efficacy amounted to 92 percent (calculation based on the 20 confirmed COVID-19 cases split between vaccinated individuals and those who received the placebo) as per the Russian Direct Investment Fund's (RDIF) statement.
(WIth inputs from agencies)