Pediatricians in the United States are seriously concerned over the increasing rates of pertussis and measles among children. For example, the number of cases of pertussis among American children increased three folds in the past 10 years. This trend is attributed to the declining rates of immunization among children. Both, pertussis and measles used to be among the most common causes of death among children prior to introduction of vaccines. It has been estimated that during the past 100 years vaccines saved about 300,000,000 lives worldwide. Collective memories of the horrors of having these diseases, thanks to the vaccines have disappeared. As results, pediatricians have a difficult time convincing parents of the importance of vaccinations. Some parents don’t trust the medical community and think that chances of developing complications following vaccinations are higher than the chances of contracting pertussis or measles and some believe that their children will not be exposed to the infections, expecting others to be vaccinated. Herd immunity is a well know epidemiological phenomenon, which is responsible for the community to be protected for as long as something like 90-95% of the people in the community are immune. If the percentage of immune the population drops to below 90%, the effect of herd immunity disappears. In other words, if everyone in a given community expects everyone else, except themselves to do the right thing, the community has a good chance of loosing the herd immunity effect and exposing children to devastating illnesses. The problem is complicated by the fact that immunity against pertussis is gone by the age of 40 and adults travelling abroad can acquire pertussis and bring it back to their families unknowingly. Pertussis in adults has a mild manifestations and may go undiagnosed and untreated. There are a small number of children for whom, illnesses immunization is contraindicated, this is usually due to some underlying chronic and serious conditions. Ideally these are the children who should rely on herd immunity for their protection.
Sergei Shushunov, MD