What is herd immunity and can it help the UK beat coronavirus?

The UK's chief scientific adviser told ITV News on Friday that it is hoped the Government's approach to tackling coronavirus will create a "herd immunity" to the disease.

Sir Patrick Vallance said in an ideal scenario, 60% of the UK would become infected with Corvid-19 to help us all be "a bit protected" from the virus.

But what is the idea behind herd immunity - sometimes known as 'community immunity' or 'herd protection' - and is it a proven method to stem the spread of infections as virulent as coronavirus?

  • What is herd immunity?

When a contagious disease passes through a population in high numbers a sufficiently high proportion of individuals become immune to the disease, slowing the infection's potency.

Herd immunity is how vaccinations work; essentially it creates a protective shield around the community and helps to safeguard those who are more vulnerable.

For example, if someone with measles is surrounded by people who have all been vaccinated against measles, the disease quickly disappears again as there is no one to pass it on to.

In short, the theory is catching the Covid-19 infection could help reduce the risk to the most vulnerable in society.

Vaccinations create herd immuntiy. Credit: PA
  • How does the Government hope herd immunity will work in relation to coronavirus?

In the case of coronavirus, there is, as yet, no vaccine so it is not possible to boost the population's immunity through jabs.

What the Government hopes is its measures will ensure that the virus passes through the population in a controlled way and lower transmission rates.

Most people, Sir Patrick reassured us, would only become "mildly ill" as a result of catching the virus; some of us may show no systems at all.

By allowing over half the population to become infected, the likelihood of the disease returning, perhaps even more aggressively, reduces, government advisers say. This, Sir Patrick and other experts say, will help protect the most vulnerable among us.

  • Why is herd immunity important?

Some people in the community who are particularly vulnerable to disease, especially if they cannot safely receive vaccines.

These include newborn babies, elderly people and those with compromised immune systems.

The more of us who are resilient, the higher the chances of fighting a disease. Credit: PA
  • Does herd immunity work?

Herd immunity in relation to vaccines absolutely does work. Vaccinations have dramatically reduced the risk to the population from many deadly diseases, in the case of some diseases such as small pox, herd immunity through vaccination has eliminated it from the population entirely.

Before mass immunisation 'measles parties' were popular among those who thought exposing children to contagious diseases at a young age would be safer than leaving them to catch it as an adult.

But, while these parties have made a comeback (the idea still resonates with anti-vaxxers) deliberately putting people in the path of an infectious disease is generally discouraged by public health officials in favour of vaccination.

Herd immunity does not give as high a level of individual protection as immunisation does, but with no vaccine currently available, this is not a option the world has right now.

Coronavirus: Everything you need to know