Coronavirus: Why talk of a 'second wave' of COVID-19 may be premature
There is no agreed definition of a second wave - so can we say with any certainty that we are experiencing one?
Saturday 1 August 2020 16:20, UK
The rise in cases across Europe has prompted some people, including Boris Johnson, to talk about a "second wave" of COVID-19.
But there is no agreed definition of a second wave - so we cannot say with any certainty that we are experiencing one.
Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, said: "As far as I know, there are no agreed definitions about 'second waves' or 'spikes', and if there were I suspect it would not be easy to distinguish them until several weeks have elapsed.
"Much of the thinking about second waves is derived from previous influenza epidemics and pandemics, and the patterns may not be the same for COVID-19 - SARS-Cov-2 is a very different virus to the different influenza viruses."
We are seeing localised outbreaks of coronavirus in some countries and the response to these spikes, with travel restrictions or by imposing quarantine upon travellers returning from these areas, might make it feel like we have come through the worst and now we are bracing ourselves to go through it all over again.
The language prompting debates of second waves is unhelpful, according to the World Health Organisation (WHO).
Margaret Harris, a WHO spokesperson, said: "We are in the first wave. It's going to be one big wave.
"It's going to go up and down a bit. The best thing is to flatten it and turn it into just something lapping at your feet.
"But at the moment, first, second, third wave, these things don't really make sense."
So are we still in the first wave?
Yes, that is certainly the widely held view.
What we are seeing here in the UK in places like Leicester, Oldham and Blackburn with Darwen - and in Europe - are localised flare-ups that could have been predicted with the easing of lockdown.
Professor James Naismith, director of the Rosalind Franklin Institute, said: "We all need to be clear what we mean when we discuss 'second wave'.
"The UK has never been free from infection, we have had hundreds of cases per day every day since March. However, the number of cases measured today are not comparable to those detected in March.
"In March, we had far too little testing, as a result, the numbers in March massively underestimated the number of infections.
"Although the current testing regime does not catch every positive case, we do have much better sight of the virus.
"The increase in cases was to be expected, as the lockdown eases, the opportunity for the virus to spread will increase."
Will the UK experience what is happening in Europe?
At the start of the year, we watched the virus spreading across Europe and tried to predict what might happen in the UK.
It was necessary to learn how health systems in different countries coped with the pandemic to help us to shape our response.
This time it is different. We are much further along the timeline, there is no lag between what is happening on the continent and here. Also, each country has taken a different approach to dealing with localised outbreaks.
So all of this makes predictions and trends more difficult.
What is pretty certain is that there will be further outbreaks and it is how these are managed that will determine what happens next.
The prime minister has been criticised for the action he has taken on imposing quarantine rules for travellers returning from Spain. But restricting movement is still seen as the most effective way of preventing the virus from spreading.
Dr Michael Head, senior research fellow in global health at the University of Southampton, said: "It is a little early to say definitively whether some European countries, such as Spain or Germany, are experiencing the start of a second wave, or simply seeing spikes in their caseloads.
"The long-term decline to zero cases of COVID-19 will always see bumps in their graphs within the downward trend. It is up to all of these countries to ensure that these are only 'spikes' and not a 'second wave'.
"Therefore, we simply have to implement a proactive approach that will rapidly squash any emerging outbreaks. This includes the need for rapid case detection, effective contact tracing, immediate sharing of data across public health authorities, and will sometimes require local lockdowns or quarantine measures."
What should we be looking out for?
We should not be looking for something new or different.
The view is that we have to accept that our lives have changed and, until a vaccine is found, we must learn to live with the virus and be as ready as we can be for more serious, larger outbreaks - especially as winter approaches.
Professor Jose Vazquez-Boland is the chair of infectious diseases at the University of Edinburgh. He said: "What we are facing is a comeback of community transmission after removing the lockdown measures.
"We have to be clear that the efficacy of lockdowns is only temporary. There will be a resurgence of new cases every time social restriction measures are lifted as long as the virus remains in circulation.
"What is important to consider is that we will most likely have to deal with new peaks of incidence unless SARS-Cov-2 is eradicated.
"These peaks may become shallower if previously exposed people become immune, but whether this happens is unclear at this point.
"Until a sufficiently efficacious vaccine becomes available, the only way we have to achieve COVID-19 eradication is through the mass, systematic, regular screening of the population."
So what next?
The arrival of summer, coupled with the easing of restrictions, makes it feel like the end of the first cycle.
And now, just as we begin to enjoy our new freedoms, rising infection rates will make people nervous about a return to where we were a few months ago.
But that is not what is happening. It is not a steep incline upwards towards a peak, followed by a sharp drop.
Instead the line is more likely to be a series of waves and just how big they are will depend on how much we stick to the rules around things like social distancing and the success of testing regimes.
Dr Gail Carson - head of the International Severe Acute Respiratory and Emerging Infection Consortium and a consultant in infectious diseases at the University of Oxford - said: "We knew that SARS-Cov-2 had not been eliminated and that we were to learn to live with it using a package of measures including social distancing, contact tracing, hand hygiene and cloth mask wearing, possibly even localised versions of lockdown.
"The mention of 'waves' usually refers to influenza epidemics and a seasonality when it peaks in the cooler, winter months.
"This is not flu, it is SARS-Cov-2, and we are still learning about how best to manage it. However, we are seeing that some measures work, but the situation appears fragile and therefore we must maintain vigilance.
"A few months ago I mentioned, as did others, the need to scale up our preparedness for a resurgence, further peaks, upticks or waves. This is a unique situation as we find ourselves recovering, responding and preparing all at the same time."