The search for a vaccine to safeguard the world against Covid-19 has prompted unprecedented activity. Tens of billions of dollars have been pledged and poured into scores of projects backed by governments, pharmaceutical companies, academic laboratories and independent researchers. Political leaders are talking up developments, none being more optimistic than United States President Donald Trump, who is confident his country will have one “within the year” . Compressing a process that normally takes a decade into so tight a time frame is unheard of, and scientists are being more circumspect, with some warning there is no guarantee of a breakthrough and that we may have to learn to live with outbreaks. Driving the efforts are uncertainty, profits, politics and pride. The world has not experienced a pandemic on such a scale in living memory, and the health and economic impacts have governments and populations frightened as never before. A fundraising conference organised by the European Union earlier this month that brought together world leaders, monarchs, philanthropists and celebrities garnered pledges of US$8 billion to fund laboratories that have made promising progress in developing a vaccine. It was the first major international effort for a coordinated approach, but the US did not participate, highlighting the divergent and often competing national strategies under way. Coronavirus vaccine: WHO to issue guidelines on human challenge trials That should ring the first alarm bell for those pinning their hopes on a vaccine. The US and some other governments have made plain that their populations will be the first to receive treatment. Scaling up production to the billions of doses needed has never been done before in a limited time frame, and so represents a further challenge. But there are scenarios officials are loathe to suggest – that no drug will ever be developed or that if one appears, it fails to pass tests for efficacy and safety. There are viruses that fit these categories, among them HIV and all of the coronaviruses, including the common cold and Ebola and of which Covid-19 is a variety. But many health experts are confident that a vaccine will be developed. Their optimism stems from the unparalleled efforts under way and research showing coronaviruses do not mutate easily. But scientists also caution hopes should not be too high and that governments need to be prepared for treatments taking years or even decades to develop. In the short term, that will mean the focus has to be on testing and tracing and financial resources need to be put into producing equipment that is inexpensive, accurate and able to provide quick results. Until there is a vaccine, existing methods to keep the disease at bay will have to continue. We should be prepared for long-term mask-wearing, hand-cleaning and social distancing. Help us understand what you are interested in so that we can improve SCMP and provide a better experience for you. We would like to invite you to take this five-minute survey on how you engage with SCMP and the news.