Healthy immune systems work best when exposed to microbes. So what will lockdown have done to our resistance to germs?
Every time you kiss another human being intimately for 10 seconds, more than 80m bacteria are transferred from mouth to mouth. If you’re at a party and double dip your tortilla chip into the salsa three times, around 10,000 bacteria will be transferred from your lips to the dip. Say “hi” to your co-workers as you sit down at your office desk and you’ll also be greeted by over 10m bacteria on its surface.
Disturbing as these figures may seem, many scientists believe that exposure to these microbes helps fine-tune our immune systems – the network of cells and molecules that protect us from diseases. In 1989, epidemiologist David Strachan first proposed the “hygiene hypothesis” – the idea that being too clean causes defects in the immune system, leading to a rise in inflammatory diseases, such as asthma and allergies. While Strachan’s theory is debated and hygiene saves countless lives, decades of data support the idea that exposure to microbes helps the immune system develop.
