In the news             July 15, 2020

A few days ago I wrote about herd immunity, pointing out that if it comes about naturally it requires a very long time and it is temporary, whereas if it can be accomplished by a continual immunization program it is likely to occur relatively quickly and become permanent. For example, when immunization against the pneumococcus bacterium, a cause of minor infections such as ear infections and major ones such as meningitis and bacteremia (invasion of the bloodstream) became routine in children the incidence of pneumococcal pneumonia caused by vaccine strains among adults diminished significantly.

In the case of COVID-19 we need to think about children for another reason: they seldom become seriously ill from this new coronavirus unless they too have an underlying condition such as heart or lung disease. If we compare COVID-19 with chickenpox it reveals why opening the schools now will have significant value long-term.

Until the chickenpox (varicella) vaccine was developed in 1995 it was rare for anyone to reach adulthood without having experienced the disease. The illness is generally so mild in children that parents often staged “chickenpox parties” in the neighborhood to “get it over with.” Unfortunately about 150 children in the United States succumbed to the disease or to secondary infection every year. The story was quite different in adult victims, about twenty percent of whom developed chickenpox pneumonia and whose risk of dying was far greater. In some years prior to release of the vaccine an adult was 25 times more likely to die from chickenpox than a preschool child. Now that the virus has almost disappeared there have been almost no deaths due to chickenpox in this country in recent years.

How does this relate to COVID-19? Fatality rates begin to increase after the age of twenty; there is a dramatic rise beyond age sixty. Those beyond the age of eighty have the highest risk. In each of these age groups there is a progressively increasing incidence of type 2 diabetes. In the past few days there has been a cluster of medical journal articles (that I will discuss in next Saturday’s Pandemic Perspective blog) indicating that elevations of blood sugar even in persons who have not been diagnosed with diabetes increase the risk of severe disease and death. Obesity rates increase with age and it is a high-risk factor that often leads to the dreaded cytokine storm.

We should not fear the exposure of children to SARS-CoV-2. They have an innate resistance to severe disease, just as they do against chickenpox and they do not have the risk factors that are present in the vast majority of older adults. Further, as we have seen in other viral infections, the natural disease is likely to result in longer and stronger immunity than the vaccine-induced stimulus. A clear example is mumps, whose vaccine-induced immunity wanes dramatically during adolescence but in which natural infection produces lifelong immunity. By protecting children from COVID-19 infection we may be setting them up for a greater risk of disease when they become adults, whether or not they receive the COVID-19 vaccine.

Lifestyle

            Memory loss. Is this the worst annoyance of aging?

We dread it more than death, fearful that having difficulty in remembering names is a prelude to dementia. The prospect of becoming unable to recognize loved ones and to be incapable of managing the day-to-day routines of living is terrible to imagine. The good news is that we can do something to ward off memory loss and postpone the onset of Alzheimer’s disease and vascular dementia. Although Alzheimer’s disease has a strong genetic component, vascular dementia has little to do with aging; it is the product of the modern lifestyle and comprises about one-half of dementia cases.

Contrary to what I was taught in medical school, we can form new brain cells throughout life by engaging in physical exercise and we can increase connections between brain cells many-fold by engaging in taxing mental activity.

Exercise is important in maintaining normal body weight. Overweight and obesity lead to a loss of brain volume; excess body fat increases the risk of type 2 diabetes by a factor of eighteen (!) which leads to blood vessel damage within the brain. That in turn leads to starvation of brain cells and increased brain cell death.

In other words, regular, moderate physical activity – 4 or 5 times a week for at least one hour at an intensity that works up a sweat – not only reduces obesity but grows new brain cells and supports the health of old ones.

Good nutrition is also critical, especially omega-3 fats, abundant in fish (or a supplement if you just don’t like fish!)

Stimulate brain health by learning a new language, how to play a new musical instrument, reading, puzzles and games.

Okinawa has the highest percentage of centenarians on the planet, people who live beyond 100 years. They can take care of themselves and they can remember the names of their great-great-grandchildren. What do they have in common? Few labor-saving devices; they carry out most chores by hand or with simple tools. They eat almost no red meat and no refined grains or sugar; most of their calories come from plant foods.

A pretty simple lifestyle, and it works.