I thought it would be best to alternate my health columns between policy issues affecting health care and pressing health care problems affecting all of us.

From the beginning of the human race, mankind had to deal with diseases. Infectious diseases were the most common threat to humans.

This was made more serious by the development of urban centers. Pathogens or disease-causing agents that had little significance during the nomadic period of the human race became a terrible scourge as humans gathered in cities. Bubonic plague, yellow fever and cholera decimated populated centers all over the world. In the U.S., epidemics of yellow fever and cholera in Philadelphia, New York and New Orleans caused thousands of fatalities in the 1700s and 1800s.

As urban centers became larger, the mortality increased and other pathogens became important players. It is estimated that more than 500,000 people died in the U.S. during the influenza outbreak of 1918.

As public health measures, vaccines and antibiotics were developed and put into use, many of these diseases declined or were completely eliminated. Smallpox and polio are two of the most recognizable examples. The control of these conditions was translated into a dramatic increase in human longevity, especially in the Western world.

The threats affecting our modern environment are very different than those seen in older times. Emerging new infectious diseases like HIV or West Nile virus and reemerging old diseases (but now resistant to antibiotics) are now a major health concern.

In addition, our increased longevity and significant changes in lifestyle and behavior have made us more vulnerable to noninfectious chronic diseases and degenerative conditions. The most common diseases are now: cancer, heart disease, stroke, hypertension, diabetes, noncancerous pulmonary conditions and mental illness.

These conditions added to unintentional injuries and suicides constitute the most common modern causes of death. The dramatic increase in diabetes and cardiovascular diseases are mostly related to the increase in obesity rates.

As result of all these changes in the spectrum of diseases, the practice of medicine and the provision of health care have undergone a huge shift. We have gone from an almost exclusive dedication to the treatment of acute conditions to the management and prevention of chronic conditions.

In addition, the pharmaceutical and surgical treatment of many conditions has become more complex, more effective and certainly more expensive. To add to the complexity, in older times medications were not particularly effective but in general were devoid of toxicity. We now have far more effective medications but the possibility of serious side effects and interactions with other medicines are more likely.

Although this is a difficult issue from a public health perspective, there is clarity in what an individual can do to minimize the possibility of acquiring some of the most common conditions.

Children and adolescents must be immunized. With the exception of the extremely rare allergic reaction, vaccines are safe. There is no serious evidence of adverse effect of vaccination.

The opposite is actual the case, some conditions seldom seen before are now reemerging due to the insufficient vaccination of some populations like measles and whooping cough. For instance, the incidence of whooping cough in the U.S. in 1990 was less than 2 per 100,000 people. In 2010 the incidence was 10 per 100,000 or about 28,000 cases nationwide.

Although children and adolescents are the major targets of vaccination programs, adults can also benefit by vaccination. In some cases, like tetanus, this may be a booster to a previously given vaccine.

Although tetanus is a rare condition, half of all cases diagnosed in the U.S. are among people older than age 65. Although most people were vaccinated against tetanus as youngsters, we lose our immunity as we age. Unless there are contraindications, which are very rare, adults should receive a tetanus booster every 10 years.

New vaccines offer the possibility of protection against diseases, which in the past were unavailable like the vaccine against the human papilloma virus (HPV). This virus is responsible for most of the cases of cancer of the uterine cervix.

We must also receive vaccinations against conditions which are rare in younger adults but more common in seniors like pneumococcal pneumonia. All adults older than 65 years of age should receive the pneumococcal vaccine.

However, despite important pharmacologic developments most of what we can do to remain healthy is individual decisions related to our lifestyle. The avoidance of cigarette smoking and other tobacco products, consumption of alcoholic beverages in moderation, adequate diet, healthy body weight and appropriate exercise are the key elements of wellness and prevention.

We will focus future columns in some of these specific prevention guidelines.

If you have a suggestion for a future topic for Dr. Manetta to address, send an eamil to [email protected].