Vaccines are our best hope for controlling Covid-19. But they should be delivered in ways that we know are effective
The Covid-19 pandemic has been fraught with uncertainty and missteps, and for every scientific advancement that has moved us forward, failures to appreciate and clearly communicate the nuances have set us back. This month, we received the welcome news that mRNA vaccines are safe and protective against symptomatic Covid-19. As part of their submissions to the United States FDA for emergency use authorisation, both Pfizer/BioNTech and Moderna included a compelling finding: that the vaccines provided some protection just 14 days after the first shot.
Based on these observations, academics and lawmakers have been seduced by the idea of reducing the two-dose schedule for mRNA vaccines to just one dose, delaying the second dose until more people receive the initial immunisation, or even decreasing the dose of vaccine by half, all with the goal of getting more shots into more arms as quickly as possible. The notion of maximising the number of vaccinated people by these methods has rapidly gained support. In a time of crisis, regulators might be justified in making a decision such as this with little data in order to make the most of limited vaccine supplies and protect as many people as possible. However, in this case, they are not, both because it’s not supported by the data that we do have, and because it doesn’t address the actual problem currently facing the UK, the US, and Canada, which is the distribution of existing supplies.