If we isolated for years perhaps, but not a few months!
For most people it's no big deal, but I am somewhat concerned about babies born at the beginning of social distancing.
The world's foremost leukemia expert has actively told people in the past few years to get babies exposed to plenty of bugs in their first year, because there appear to be window periods for the immune system where not being exposed to enough stuff raises the risk of autoimmune conditions in the long term.
www.theguardian.com/science/2018/dec/30/children-leukaemia-mel-greaves-microbes-protection-against-disease
Acute lymphoblastic leukaemia is caused by a sequence of biological events. The initial trigger is a genetic mutation that occurs in about one in 20 children. For full leukaemia to occur, another biological event must take place and this involves the immune system.
“For an immune system to work properly, it needs to be confronted by an infection in the first year of life,” says Greaves. Without that confrontation with an infection, the system is left unprimed and will not work properly.” And this issue is becoming an increasingly worrying problem. Parents, for laudable reasons, are raising children in homes where antiseptic wipes, antibacterial soaps and disinfected floorwashes are the norm. Dirt is banished for the good of the household. In addition, there is less breast feeding of infants and a tendency for them to have fewer social contacts with other children. Both trends reduce babies’ contact with germs. “When such a baby is eventually exposed to common infections, his or her unprimed immune system reacts in a grossly abnormal way,” says Greaves. “It over-reacts and triggers chronic inflammation.” As this inflammation progresses, chemicals called cytokines are released into the blood and these can trigger a second mutation that results in leukaemia in children carrying the first mutation. “The disease needs two hits to get going,” Greaves explains. “The second comes from the chronic inflammation set off by an unprimed immune system.”
I do think we will need to keep an eye on this cohort.
In Japan we never had a full lockdown and are coming back to normal right now so this is not such a concern for me, but I have made a point of getting the kids exposed to plenty of dirt. Lots of play in parks and other green spaces, and gardening on the balcony.