Guess what happens when a population stays home from work and school to avoid communicable illness.  When they mask up, physically distance, and use good handwashing techniques to slow down the spread of viral illness.  The transmission of communicable illness decreases.  But viruses don't just go away.  They mutate and stack up in line, waiting for their chance to infect an immunologically weaker population.  We are currently "paying the immunity debt" as a consequence.

With isolation being replaced by socialization, the next-in-line viruses are spreading.  Many of us have been relatively healthy for a couple of winters.  But now we are fighting viral illness that is striking more frequently and have longer lasting symptoms than in the past.

A virus's primary function, like most life forms, is survival.  A virus mutates at an astounding rate.  When a virus mutates, it changes in transmissibility and virulence.  If highly virulent, the virus may kill off its host before it transmits to the next host.  This is not optimal for survival of the virus.  Think Ebola.  A very transmissible virus may fly through a population with very little morbidity.  This is great for survival.  It's the reason we haven't come up with a vaccine for rhinoviruses, the most frequent cause of the "common cold."

Our immune systems are constantly updating, keeping up with these mutations.  Frequent viral exposures allow for us to keep up with these changes in virulence.  But the viruses are incrementally weaponizing as they've backlogged.  With our lack of exposures, we are not naturally increasing our immune system's defensive capabilities. 

Seasonal flu shots could help assuage the problem, but they can be hit-or-miss.  The CDC's National Center for Immunization and Respiratory Disease review from October 27, 2022, going back to 2009, reveals anywhere from 60% vaccine effectiveness in 2010–2011 all the way down to 19% the winter of 2014–2015.  Overall, the average effectiveness over the thirteen years reviewed is around 40%. 

Respiratory Syncytial Virus, known as RSV, is racing through the U.S. currently.  Typically a winter virus, it started in late summer this year because of our "immunity debt."  Not only is it out of season, but it is more noxious than in years past, also because of the "immunity debt."  This has led to an increase in complications of RSV, such as bronchiolitis, croup, and pneumonia.  RSV is usually an illness of the very young, but it can infect all ages.  It will be a major player in grandparents suffering after holiday visits from coughing grandchildren.

Other viruses are pushing their way up in line.  Respiratory pathogens like parainfluenzas, influenzas, adenoviruses, and other rhinoviruses are here, too.  Enteroviruses, the "G.I. bugs" terrorizing schools, are here as well.  All are more virulent than usual for the same reasons.

 As a population, it will take a couple of years to "catch up" on our immunities, normalize our ability to fight viruses as individuals and communities.  The period until then will not be pretty, as viruses will be more deadly and easier to catch.

This is another foreseeable result of our government's COVID-19 response.  For a couple of years, we have been suffering from this federal overreach.  Add the "immunity debt" to this long, sad list.

Image via Public Domain Pictures.