“The vaccine (for chicken pox) was introduced in the 1990s. … ‘It is an entirely preventable disease. We don’t need to have chicken pox circulating in our environment.’ ” – Yarmouth pediatrician Dr. Laura Blaisdell, as quoted in the May 16 Portland Press Herald article “Chicken pox outbreak reported at day care center in Westbrook.”

An outbreak wreaks havoc on the most vulnerable populations: children under age 1, who are too young to be vaccinated, and the many children and adults who are immunity-suppressed for other medical conditions. Illness for these populations has lasting consequences that extend beyond the individual. Parents will need to stay home to care for sick children, or stay home with healthy children who can’t risk going to school and getting sick.

This is why herd immunity is so important for all communicable diseases that we have vaccines for. Vaccines are safe. The Red Cross and U.N. have been using them for decades overseas. This is how our military protect service members from malaria, yellow fever and other parasitic diseases.

Vaccines do not and never have caused autism. “Opt-out” is a disaster. We must educate our neighbors, our legislators and our governor about the true cost of opting out of lifesaving vaccinations. Our lives depend on it.

Bonnie S. Johnstone

retired registered nurse

Portland