The race for a Covid-19 vaccine has four candidates close to a winning jab, with some getting ready to roll out before the end of 2020. But what do the reported efficacy results mean and how much will doses cost?
In the fast-paced world of Covid vaccines, November was particularly busy. The early data of four jabs were announced, with most showing efficacy of 90% or higher. One has already been granted approval for emergency use in the UK.
A 90% efficacy means that nine in 10 people who received the shot in trials, not a placebo or dummy vaccine, did not develop Covid symptoms or were protected from the disease.
A vaccine is our most powerful tool in the fight against Covid-19 and our biggest hope for at least some normality.
But the data we have so far are not final. These results were shared in press releases, not in peer-reviewed scientific journals. Although the urgent need for a Covid-19 vaccine has necessitated the release of the data as they become available, the figures can change as they go through more checks and balances.
There are also questions that we can't answer yet, such as how long the immunity...