Herd Immunity as a COVID-19 Exit Strategy

Herd immunity is an epidemiological concept that describes the state where enough people are sufficiently immune to a disease that the infection will not spread within that group (e.g. for the MMR vaccination, that means 92-95% of the population needs to be vaccinated).

What if we don’t have a vaccine?

A further theory has been raised that if enough people (60%+) get COVID-19, recover and develop immunity, then then we will achieve natural herd immunity.

Sounds good, what’s the catch?

- Time. Any strategy would need to be tightly controlled or else 1% would die, 10%+ would be hospitalised and our healthcare systems would fall apart. Prof Neil Ferguson from Imperial College London estimates it would take 2 years to reach a critical point of infection. Not good news if you are in a vulnerable group and need to self-isolate for two years!

- Immunity. We aren’t sure yet if contracting COVID-19 make you immune. More worryingly, the virus might mutate or new viruses develop.

- Long-Term Impact of COVID-19. We don’t know the long-term impact of contracting COVID-19. Perhaps nothing for many; but we know that COVID-19 goes beyond just infecting the lungs but can also impact other organs such as the kidney, liver and brain.