If we were to once again live in the pre-vaccination era rampant with epidemics of polio, measles and smallpox, few would hesitate to vaccinate themselves and their families.

Too many of us have become complacent or have determined that the risks of vaccinations outweigh the benefits. As a result, measles has begun to spread.

New York has diagnosed over 200 cases during the past several months, more than has been seen there in decades. There were 31 cases diagnosed during the past week in Williamsburg, a suburb of Brooklyn. It has now spread to four counties in New Jersey. Two cases were diagnosed on Hawaii island several weeks ago.

The truth is that while vaccines are not without risks, they have made a major contribution to global life expectancy, which has doubled since the first vaccine was developed just before 1900. As a medical student at UCLA, I was mentored by the son of Jonas Salk, who invented the long-awaited polio vaccine. I recall my father telling my mother that the polio vaccine had finally come out, and one evening when I was all of 4 years old, we walked to the nearby school where thousands of white sugar cubes in disposable paper cups where laid out for the public. We all took one.

Prior to the polio vaccine, parents kept their children out of public swimming pools in the summer and would even send their children to relatives in the countryside when school was out. FDR, who served as president from the Great Depression to the end of WWII, suffered the permanent effects of polio from an early age. He felt it made him look weak, and made every effort to prevent the public from seeing him in his wheelchair or leg braces.

When everyone took their sugar cube with the polio vaccine, the spread of this disease essentially stopped. The problem is that when herd immunity is lost, the risk profile changes. Herd immunity is what happens when enough people in a given population have been vaccinated or have become immune to a given illness. Depending upon the specific vaccination, that proportion must be from 83% to 94%. The point is that when a population has herd immunity, even if not every individual is immune, the serious illness in question in unlikely to spread. However, once the portion of the vaccinated population drops below a certain percentage, herd immunity is lost. This is the reason for the recent spread of measles today.

The people of Hawaii are especially vulnerable to public health epidemics when herd immunity is lost because we receive nearly 10 million visitors per year from every corner of the globe. High population density is another risk factor. Waikiki, where the largest number of visitors stay, is in the center of the south-facing shore where the lion’s share of our island society lives and works.

Additional risk factors for resurgent epidemics of diseases once thought to be eradicated or under good control include the health effects of climate change, including shifting weather patterns, natural disasters, food and water insecurity and resultant human migrations. Also, once an epidemic hits Hawaii, the state is particularly vulnerable to running out of medical resources especially if shipping lanes or air traffic are curtailed.

Health risks for infectious disease go up in the summer here as the result of Hawaii’s peak visitor season and because Hawaii residents travel more because the children are out of school. Now is an opportune moment for the ohana to follow up with a health provider to discuss what vaccines may be recommended. It is also a good time to ask any questions you might have about their risks. If the majority of us follow through and become current with recommenced vaccines, we will protect not only our own health. We also will be doing our share for the public good.

Ira “Kawika” Zunin is a practicing physician. He is medical director of Manakai o Malama Integrative Healthcare Group and Rehabilitation Center and CEO of Global Advisory Services Inc. Please submit your questions to info@manakaiomalama.com.