It would be hard to overstate the importance of developing a vaccine to Sars-CoV-2 – it’s seen as the fast track to a return to normal life. That’s why the health secretary, Matt Hancock, said the UK was “throwing everything at it”.
But while trials have been launched and manufacturing deals already signed – Oxford University is now recruiting 10,000 volunteers for the next phase of its research – ministers and their advisers have become noticeably more cautious in recent days.
This is why.
Why might a vaccine fail?
Earlier this week, England’s deputy chief medical officer Jonathan Van-Tam said the words nobody wanted to hear: “We can’t be sure we will get a vaccine.”
But he was right to be circumspect.
Vaccines are simple in principle but complex in practice. The ideal vaccine protects against infection, prevents its spread, and does so safely. But none of this is easily achieved, as vaccine timelines show.
More than 30 years after scientists isolated HIV, the virus that causes Aids, we have no vaccine. The dengue fever virus was identified in 1943, but the first vaccine was approved only last year, and even then amid concerns it made the infection worse in some people. The fastest vaccine ever developed was for mumps. It took four years.