The new restrictions announced by Boris Johnson yesterday, including the closing of restaurants and pubs at 10pm and increased use of face coverings, fall short of a “second lockdown” but signal that life is still far from returning to normal.
While England’s true number of cases is likely much lower than in the spring due to increased testing, it is the ski-jump trajectory of recent case growth that gives epidemiologists palpitations. The cruelty of exponential growth, with cases doubling at regular intervals, is real. The flipside is that reducing transmission, even a little, can have a huge payoff in reducing the total number of infections.
But to head off exponential growth, we must act sooner rather than later, especially as it can take a week or more to detect cases of Covid in people who have already spread it to others. As we saw in March, hesitation, even by a week, can have an outsized impact on the resulting scale of infections, hospitalisations and deaths. The first minister of Scotland, Nicola Sturgeon, announced stricter measures for her country on Tuesday, limiting non-essential visits between households. Yet England has hesitated to do the same. It seems inevitable that this measure will soon become necessary, as Chris Whitty has recently suggested.
What exactly we as a society should do to forestall this “second wave” is still up for debate. Earlier this week, different groups of scientists published two open letters offering conflicting views about how the UK should deal with the virus in the coming months. The first letter urged tactical shielding of the most vulnerable with fewer restrictions elsewhere, while the other recommended a strategy of overall virus suppression.
While it’s important to balance controlling Covid with protecting the economy, the idea of shielding only certain groups while letting the virus rip through the rest of the population is misguided at best. We do not live in age-segregated bubbles, nor could we achieve this on even a temporary basis. Younger people work in hospitals and care homes and live in multigenerational households, carrying infections with them. The higher the rate of community transmission, the more inevitable this spillover will be – and the greater the number of resulting deaths.
What’s more troubling is the presumption that Covid-19 is harmless and won’t scar younger people. This belies the mounting evidence that “long Covid” can have serious chronic impacts among younger generations. And the idea that natural “herd immunity” could be a path out of the current crisis, voiced by some scientists, relies on unproven assumptions about how long immunity from Covid lasts. Even the most optimistic belief that immunity may last a year or two, as with other coronaviruses, would still mean that previously immune individuals could become susceptible on a regular basis, renewing their ability to transmit the virus to more vulnerable people.
Without suppressing the virus, strategic shielding won’t magically return us to a pre-Covid economy. While some members of society, especially young people, have shown themselves more willing to take risks as restrictions eased, many have also weighed the risks in favour of continued takeaway food and Netflix binges. Many people below the age of 65 are unlikely to want to offer themselves up to the experiment of herd immunity.
The idea that avoiding lockdown measures could be better for the economy also overlooks an important fact: unless we suppress the virus, more people will voluntarily “shield” themselves and their loved ones inside, potentially leaving us with the worst of both worlds. With dozens of viable vaccine candidates and treatments on the horizon, suppressing infections in the near term is both humane and sensitive to the economic effects of an unfettered epidemic.
As we’ve known for many months, the path out of the pandemic relies on using a full toolkit of strategies to buy time and deprive the virus of the fuel it needs: close social contact. It seems increasingly clear that inhaling aerosols or droplets from infected individuals talking or breathing plays a bigger role in the spread of coronavirus than surfaces. This makes masks, ventilation and avoiding crowded indoor spaces a high priority, especially as autumn and winter push more people indoors.
Rather than a lockdown switch that we turn “on” or “off”, we should be considering a panel of controls to dial up the activities that are most important to keep open, such as schools and healthcare, and those that are the least risky for transmission, such as outdoor leisure and shopping with masks. We should dial down activities strongly associated with transmission and superspreading, such as events that involve being indoors for long periods of time or loud talking.
Sustained close contact, such as dining, is a much riskier activity than shopping or brief community encounters. Sadly, high-risk activities include large social and family gatherings with lots of intimate contact, and events that the hospitality industry, which will need economic support through the next six months, rely upon. Weddings and parties are among the events most often linked to large clusters. While the rule of six is supposed to deter large household gatherings, following Scotland’s lead in reducing indoor contact across households could be an important short-term tool for snuffing out current transmission chains. And in the medium-term, when transmission is lower, home visits with small numbers and proper attention to ventilation, distance and masks should be something we can dial up.
The time lag between transmission, incubation and testing makes early measures even more important. In turning the dial, we won’t know if we have undershot our target until weeks later, while exponential growth accrues in the meantime. The restrictions needed to bring down even higher levels of transmissions will be more severe, and required for longer than if they had been enacted earlier. Cutting off early exponential growth therefore pays dividends, by reducing the duration of restrictions and economic costs in the long run.
In the spirit of early and effective action, the measures announced yesterday should be strengthened to further restrict indoor dining and home visits in England, and encourage the use of face coverings in all indoor settings including schools, where children and teachers spend long periods indoors with close contact and where distancing can’t necessarily protect them from aerosol transmission. Keeping kids in school should be a priority, using all the layers of protection at our disposal. To do so requires sacrifices in other areas of society, a delicate balancing of the dials to see us through the winter to come.
• Jennifer Dowd is a professor of demography and population health at the University of Oxford
