A second wave of coronavirus could be “more severe” than the first and may spread more rapidly if it arrives in winter, England’s chief medical officer has warned.
Every country seeking to ease lockdown measures now must negotiate an “extremely difficult balancing act” to keep the pandemic under control, Professor Chris Whitty said in an online Gresham College lecture.
In particular, the virus reproduction “R” number must be kept below one – meaning each infected person could expect to pass it to fewer than one other person on average.
Prof Whitty said: “We need to make sure that R does not go back above one. Because if not we will go back to a second wave.
“It is entirely plausible for a second wave to actually be more severe than the first if it is not mitigated.
“Every country has got an extremely difficult balancing act, and we all need to be honest about the fact there are no easy solutions here.
“Covid-19 is a very long way from finished and eradication is technically impossible for this disease.”
Outlining several key unknowns about coronavirus, Prof Whitty highlighted seasonality, saying: ”There may be a seasonal element to this, we don’t know, it’s too early with this virus.”
He went on: “It’s not just in Game Of Thrones that winter is always coming – it is also true in every health service.
“It may be that there’s a seasonal element and if so, for most respiratory viruses, they are more likely to be transmitted, there is a higher likelihood of transmission, in the winter.
“The winter is always worse than summer, spring and autumn for health services, and we need to think about this in terms of how we come out for the next phase.”
However, he added social distancing measures are likely to reduce rates of flu and other respiratory illnesses when winter arrives.
Other key unknowns about Covid-19 highlighted by Prof Whitty were:
– The proportion of the population which is infected without symptoms, although it is currently thought to be “actually quite low”.
– How long immunity to the virus lasts.
– Whether blood tests correlate with immunity.
– How much children contribute to spreading the virus.
– Why people deteriorate after a week and why men are significantly more likely to die than women.