As summer and summer travel wind down and families are enjoying many activities, it’s important review your child’s vaccination status with your health care provider.

With the school year almost upon us, now is a good time to ensure your child is up to date with his/her immunizations, as there have been some recent changes to the vaccine schedule and to to recommendations

regarding vaccines for travel.

Although many infectious diseases are at historically low levels here in the U.S. and elsewhere in the world, there are many areas where vaccine-preventable diseases are still endemic. We live in an increasingly mobile world, and with air travel so common, a person with an infectious disease can unwittingly expose many people both on the aircraft and in the airport terminal.

Measles is a perfect example. According to the Centers for Disease Control and Prevention, measles was declared eliminated in the U.S. in 2000. However, there are sporadic cases appearing — almost all imported from overseas by unvaccinated or undervaccinated travelers returning to the U.S. from visiting endemic areas.

Last year, there were 17 outbreaks in various communities in the U.S.

Europe has experienced a dramatic increase in measles cases, including the U.K., France, Spain and Italy. There is now a recommendation that U.S. citizens traveling to Europe are vaccinated against measles.

Generally, the measles vaccine is given to children starting at 12 months of age, but for international travel, the recommendation is to vaccinate starting at 6 months of age.

Pertussis, or whooping cough, is another vaccine-preventable disease that is making a comeback, especially in California. In adults, the illness presents as a chronic cough, but in young infants, it can cause respiratory failure and sometimes death.

Because immunity wanes as a person gets older, there is now a recommended dose of pertussis- containing vaccination (generally given as

tetanus, diphtheria, acellular pertussis combination) for adolescents and adults in lieu of the previously given tetanus booster.

Some parents question whether they should vaccinate their child, especially because disease rates are so low.

Children and adults are protected by “herd immunity” when there is a high rate of vaccination. If most people are immune to a certain disease, the disease cannot get a foothold in that community of people. However, there is a tipping point.

When enough people are not immunized and herd immunity lessens, the disease has a way in.

And, keep in mind, some people cannot be immunized.

Young infants are too young to have received certain vaccines and have not had all booster doses. Adults and children with immune suppression (long-term steroid use, taking certain medication, receiving chemotherapy for cancer, infected with HIV) cannot make enough antibodies to fight some diseases.

Another factor that determines herd immunity is that no vaccine is 100 percent effective; even fully vaccinated populations may have protective antibody levels of only 85 to 95 percent, depending on the disease.

Vaccination remains one of the most successful public health stories of the 20th century.

A recent article in the New England Journal of Medicine, titled “What We Don’t See,” discusses the impact of infectious diseases in children over the past 200 years. This is found at www.nejm.org. Other helpful websites that can answer questions about vaccines are

www.cdc.gov,www.immunize.org and the Children’s Hospital of Philadelphia website, at www.chop.edu. Enjoy these last few weeks of summer safely!

Dr. David Coggins is a pediatrician with the Geisinger Gray’s Woods practice and is on the medical staff at Mount Nittany Medical Center.