Why vaccines fail

            One of the major factors in the steep rise in life expectancy that occurred between 1900 and 2000 was the development of childhood vaccines. Today’s young physicians may never see a child with measles, polio, some forms of bacterial meningitis or chickenpox. Even the oldest physicians among us have likely never seen a child dying agonizingly from whooping cough or tetanus or diphtheria, those diseases having been vanquished before World War Two. If these diseases occur in the United States – and they do sometimes – it is usually because the patient came from a country where medical care is poor and immunization rates are much lower than they are here, or because parents have been caught up in the anti-vaxx hysteria that has been increasingly common in the twenty-first century.

            But sometimes a vaccine does fail to provide infection from the disease that almost always prevents the disease against which it is targeted. One reason is that some vaccines must be kept at specified refrigerator temperatures. When the measles vaccine was released in 1963 pediatricians noted occasionally that vaccinated children developed measles. Investigation showed that some pediatricians’ staff had placed the vaccine on a door shelf of the refrigerator instead of deep inside, which had been recommended. The slight increase in the temperature of vials kept on the door shelf was high enough to weaken the live vaccine, rendering it ineffective. The oral polio vaccine, a live form developed by Albert Sabin, has the advantage of not requiring needles and syringes that are prohibitively costly in developing countries, but it requires a “cold chain” that is also expensive in order to prevent degradation of the vaccine.

            Children who are born with a severe immune deficiency or those whose immune system is weakened by chemotherapy will not respond to the stimulus of a vaccine agent. Obesity may be a factor in the adult population, not only because obesity or its accompaniment, type 2 diabetes, degrades the immune system but because ordinary-length needles fail to reach the muscle tissue deep within a layer of fat. The result is that the patient cannot develop adequate antibodies or immune cells.

            Vaccines vary tremendously in their duration of protection. Diphtheria and tetanus vaccines provide nearly lifelong immunity but the mumps virus fails to protect after just a few years. The disturbing occurrence of numerous mumps outbreaks among young adults has prompted a reevaluation of that vaccine. Yet more evidence that mother nature keeps throwing curveballs!