By: Katia Hetter
Vaccine rates for measles, polio, diphtheria and other diseases are decreasing among US children, according to a new study from the US Centers for Disease Control and Prevention.
The rate of immunizations for required vaccines among kindergarten students declined from 95% to approximately 94% during the 2020-21 school year. It dropped further — to 93% — in the 2021-22 school year.
That’s still a high number, so why is this drop in immunization significant? What accounts for the decline? What might be the consequences if these numbers drop further? If parents are unsure about vaccinating their kids, what should they do? And what can be done on a policy level to increase immunization numbers?
To help us with these questions, I spoke with CNN Medical Analyst Dr. Leana Wen, an emergency physician, public health expert and professor of health policy and management at the George Washington University Milken Institute School of Public Health. She is also author of “Lifelines: A Doctor’s Journey in the Fight for Public Health.”
CNN: Why is it a problem that childhood immunization rates are declining?
Dr. Leana Wen: The reduction of vaccine-preventable diseases is one of the greatest public health success stories in the last 100 years.
The polio vaccine was introduced in the United States in 1955, for example. In the four years prior, there were an average of over 16,000 cases of paralytic polio and nearly 2,000 deaths from polio each year across the US. Widespread use of the polio vaccine had led to the eradication of polio in the country by 1979, according to the CDC, sparing thousands of deaths and lifelong disability among children each year.
The measles vaccine was licensed in the US in 1963. In the four years before that, there were an average of over 500,000 cases and over 430 measles-associated deaths each year. By 1998, there were just 89 cases recorded — and no measles-associated deaths.
These vaccines are very safe and extremely effective. The polio vaccine, for example, is over 99% effective at preventing paralytic polio. The measles vaccine is 97% effective at preventing infection.
We can do this same analysis for other diseases for which there are routine childhood immunizations.
It’s very concerning that rates of immunization are declining for vaccines that have long been used to prevent disease and reduce death. That means more children are at risk for severe illness — illness that could be averted if they were immunized. Moreover, if the proportion of unvaccinated individuals increases in a community, this also puts others at risk. That includes babies too young to be vaccinated or people for whom the vaccines don’t protect as well — for example, patients on chemotherapy for cancer.