Dr. Michael Ryan, the chief of WHO's health emergency program, has warned that Covid-19 may not go away for years. The top WHO official's warning causes concern.

"Without a vaccine, it could take years for the global population to build up sufficient levels of immunity," Ryan has been quoted as saying.

The novel coronavirus may become just another endemic virus in our communities, he added.

"Novel diseases like HIV have never disappeared. However, effective treatments have been developed," he said, suggesting that, if a vaccine is not invented for Covid-19, effective treatments might be a ray of hope.

The official recently was in the news for explaining herd immunity. "Humans are not herds. The concept of herd immunity is generally reserved for calculating how many people would need to be vaccinated. It can lead to a brutal arithmetic that does not put people and life and suffering at the centre of that equation," Ryan was quoted as saying.