Since May, several variants of the virus that causes Covid-19 have been detected around the world. On May 29, a new variant was detected in Vietnam, a combination of the Alpha strain found in the UK and the Delta strain first detected in India. This has faster airborne spread and is more lethal. Variants found in the UK, South Africa and Brazil were described by the World Health Organization (WHO) as variants of concern. According to the WHO, variants of the novel coronavirus are appearing more frequently, adding more uncertainty to the battle against the coronavirus. Heath experts cautioned that society must ensure that the pace of vaccination against Covid-19 is faster than it can mutate. It is urgent for countries to work on mutual recognition of Covid-19 vaccines. International vaccine cooperation is the ultimate key to beating the pandemic.