Two-tier approach could begin lockdown end

Academics from the Universities of Edinburgh and London have modelled a range of scenarios to illustrate how different restrictions could be applied to different groups. Their findings have been made available to the UK and Scottish Governments.

Segment and shield

The strategy involves segmenting the population into different risk groups – based on a person’s medical history and potential healthcare needs. Such an approach would give young healthy adults and children greater freedoms while ensuring that the most vulnerable are protected.

Researchers say lockdown restrictions could be eased for most people, as long as sufficient measures stay in place to keep transmission rates low. These would include self-isolation of people with Covid-19, quarantining affected households, contact tracing and voluntary social distancing.

The most vulnerable – the elderly and those with underlying medical conditions – would still need to be shielded from contact with anyone potentially infected with the virus.

To achieve this, people sharing a house with a vulnerable person, care workers and health professionals would need to protect themselves from infection.

Easing the measures taken during the lockdown is important as they currently have a tremendous effect on our society, but this should only be done in a way that is both safe for the people that are most vulnerable as well as for the health and safety of NHS staff. Segmentation and shielding is a possible way of achieving this: measures could be eased for a large proportion of the population, however the vulnerable population likely still needs to be protected for a prolonged period.

Bram van Bunnik

Measures maintained

The team says the risk to non-vulnerable people could be managed without resorting to lockdown. Instead, they propose a response based on appropriate and effective clinical care and proportionate public health measures.

Implementing the policy would demand high standards of hygiene and protective measures at home, and in institutions such as care homes and hospitals, the team says. Ideally, there would be intensive screening of everyone who comes into contact with the vulnerable population.

The researchers say the models are robust to a wide range of assumptions about immunity to COVID-19, but they caution that not enough is known about the build-up of immunity in affected populations. The team stresses that this aspect of the epidemic needs to be monitored very closely.

Segmentation and shielding recognises that, although social distancing impacts on the whole of society, the public health burden of Covid-19 is concentrated in a subset of vulnerable people. By targeting protection to those that need it most, the strategy helps to ensure that the health system is not overwhelmed by severe cases, while giving policy makers greater leeway to partially relax social distancing measures for the majority of the population.

Mark Woolhouse

Related links

Full paper: Segmentation and shielding of the most vulnerable members of the population as elements of an exit strategy from COVID-19 lockdown

University of Edinburgh COVID-19 Response pages