Needle in a haystack

As the hunt for a Covid-19 vaccine gathers momentum, the complexities involved pose many challenges to the researchers

- NAMITA KOHLI

AS THE WORLD eagerly awaits a vaccine for SARS-CoV-2, those who are developing the shot face several challenges in making a safe and effective product in a short time. According to the World Health Organization’s draft landscape for Covid-19 vaccines, there are 133 candidates at different stages of development. Ten of these are in the clinical evaluation stage, while 123 are in pre-clinical stages. The Coalition for Epidemic Preparedness Innovations, the global body that is funding vaccine candidates, lists 224 candidates across the globe that are being worked on using diverse technologies. The sheer numbers, and the different technologies being used, mean that the chances of a successful candidate are high, say experts.

Here is the bitter truth, though. Experts also concede that given the complexities involved in building a vaccine, a majority of these candidates are bound to fail—one would be lucky if a couple of them succeeded. In India, some 30 groups are working on a vaccine; only two or three look promising, said some top government officials.