After developing and rolling out Covid-19 vaccines at record speed, drugmakers are already facing variants of the rapidly-evolving coronavirus that may render them ineffective, a challenge that will require months of research and a massive financial investment, according to disease experts.

Executives from Moderna Inc and Pfizer Inc and partner BioNTech SE are considering new versions of their vaccines to respond to the most concerning variants identified so far. That is just one piece of the work needed to stay ahead of the virus, nearly a dozen experts told Reuters.

A global surveillance network to assess emerging variants must be built. Scientists need to establish what level of antibodies will be required to protect people from Covid-19 and determine when vaccines need to be altered. And regulators must convey what is needed to demonstrate updated vaccines are still safe and effective.

"At this point, there is no evidence that these variants have changed the equation in terms of protection from the vaccine," said Dr Michael Osterholm, an infectious disease expert at the University of Minnesota.