Why Vaccinate COVID-19 Survivors?

In these posts I use my experience as a practicing pathologist to present clear, simple, and understandable explanations of important issues relating to the pandemic amid the noise and misleading half-truths we encounter daily.  When I don’t know, I tell you.  Today, I’m asking you to help me understand something that’s been puzzling me for weeks. Why does the CDC adamantly insist that COVID-19 survivors be vaccinated?

The CDC’s statement is simple enough.  They say that there is a wide range of outcomes to SARS-CoV-2 infection, from no effect to death, and that there is a corresponding range of immune responses to infection.  Those who had mild disease, the argument goes, may not have built up the immunity necessary to fight future infections.  The vaccine, on the other hand, is a measured dose designed to stimulate an adequate immune response.  Furthermore, they assert that there is no data on how long natural immunity may last, saying, “experts do not yet know how long you are protected from getting sick again after recovering from COVID-19.”  So, they conclude, everyone must be vaccinated, even those who have recovered from COVID-19.

Simple enough, yes.  You will find this theory repeated on health websites and in the popular press, often citing compelling studies and medical experts.

But does it make sense?  Before the pandemic, did medical science ever assert that vaccine-induced immunity is superior to natural immunity?  I’ve looked.  I cannot find that assertion from any reputable source, nor can I find that assertion supported by any body of evidence.  I’m not saying that I’ve looked everywhere.  I’m saying I looked and came up empty.  If you know where it is, please tell me. 

Let me be clear about my question.  I’m not doubting that vaccine is an important tool in the war against infections generally and SARS-CoV-2 specifically.  Clearly, vaccines provide protection to individuals most vulnerable to bad disease outcomes.  Clearly, vaccines raise the overall immunity within the population, stemming the spread of infection.  An article published in Texas Medicine on the eve of the pandemic advocates for vaccine, especially childhood vaccines—mumps, measles, rubella, and the like—using a simple risk-benefit analysis.  This analysis, and many more like it within the body of traditional medical science, compare the risk of vaccine to the risk of disease.  Acknowledging that vaccines have risk and diseases have risk, vaccines generally have less risk than disease.  This is very different from introducing the risk of vaccine to individuals who have already survived the risks of infection by the virus.

There is a glaring flaw in the CDC’s argument.  True enough, experts do not yet know how long you are protected from getting sick again after recovering from COVID-19.  But neither do experts know how long you are protected from getting sick after completing a vaccine series.  How could they know either?  Neither COVID-19 nor the vaccines have existed long enough to be studied meaningfully, which brings me back to my question.  How can we say vaccine-induced immunity is superior to natural immunity?

I cannot think of any other example of this line of thinking.  We do not insist that children who have had chicken pox get the chicken pox vaccine.  We do not give hepatitis B vaccine to individuals who have had hepatitis B infection.  In fact, before giving a hepatitis B vaccine, we usually test for antibodies to make sure the individual has not been previously infected.  Why expose someone to an additional risk unnecessarily?

Are COVID-19 vaccines different from any other vaccine?  Has a new theory of immunology suddenly replaced years of observation and wisdom?  Why would the CDC, a place I know to be filled with smart, dedicated, and sincere physicians and scientists, be so insistent that COVID-19 survivors be vaccinated?  

If you know the answers, please tell me.  I would love to hear from you.