Local lockdowns will be key in COVID-19 management

Outlook

Spain’s major public health research institute, Instituto de Salud Carlos III, on July 6 unveiled the largest serological study conducted to date in Europe, including some 61,000 individuals. The study found that only 5% of those sampled had had COVID-19. The findings end debates over allowing the virus to build natural ‘herd immunity’ in the community; given that 95% of the population is still susceptible to the virus, the death toll would be too high -- more than 28,400 people died in Spain since the start of the epidemic.

One-third of the participants who tested positive for the virus were asymptomatic; that would be an estimated 1 million Spaniards. This makes controlling the epidemic difficult, so a combination of social distancing and other non-pharmaceutical interventions will be needed until a vaccine becomes available. Lockdowns of whole cities or regions will be a key strategy, probably driven by outbreaks in cities; rural areas will have lower incidence.

Impacts

• Evidence points to immunity to COVID-19 waning after three months, which means recurrent outbreaks are likely.
• Transmission is likely to increase over the winter, as colder temperatures bring people together indoors.
• Winter months could see more frequent lockdowns and stricter measures.