Does COVID really damage your immune system and make you more vulnerable to infections? The evidence is lacking

by | Jan 23, 2023 | COVID-19, News, Sheena Cruickshank | 0 comments

Our Eco-immunology Deputy Branch Lead Professor Sheena Cruickshank writes in The Conversation about the large wave of respiratory tract infections over the past two months in countries like the UK and the US, which has led some to question whether COVID damages the immune system and if measures taken during the pandemic resulted in children “missing out” on common childhood infections – creating an “immunity debt”

Professor Cruickshank looks at:

  • the impact of COVID on our immune system
  • impact of Long COVID 
  • the “immunity debt” hypothesis 

On the concept of “immunity debt” Professor Cruickshank writes:

The “immunity debt” hypothesis suggests the immune system is like a muscle requiring near-constant exposure to infectious agents to keep it functioning. So, the argument goes, a lack of exposure due to lockdowns damaged immune development, especially in children, by making our immune systems “forget” earlier knowledge. This supposedly left them more vulnerable to infections when social mixing returned to normal.


Though this idea has gained traction, there’s no immunological evidence to support it. It’s not true to say we require a constant background of infection for our immune system to work. Our immune systems are immensely robust and powerful. For example, immune memory to the 1918 influenza pandemic was still evident after 90 years.


It’s also not strictly true to say children weren’t exposed to viruses during the early pandemic. Lockdowns didn’t commence until after waves of the usual winter respiratory infections in 2019/2020, and schools in the UK reopened in autumn 2020 with variable preventive measures, so children were still exposed to infections, including COVID-19.

You can read the full article here