Reducing the Risk of Vaccine Preventable Diseases During the Pandemic

In addition to the myriad direct adverse consequences of the COVID-19 pandemic is the negative effect on preventive health care, including routine immunizations for children and adults.

Providing routine vaccinations at the recommended ages is critical to keeping our children and our communities healthy. The same is true for vaccinations for adults. Unfortunately, the COVID-19 pandemic has suppressed many well-care visits to doctors’ offices and clinics. The result has been a worrisome decline in immunization rates, prompting concern among public health officials that Michigan communities are at increasing risk for cases and outbreaks of preventable diseases.

One disease that especially has experts worried is measles. Measles is highly contagious and in the past was a very common - and deadly - childhood illness. Millions of cases occurred in the United States each year with up to 500 measles-related deaths. Measles incidence declined dramatically following the licensure of the measles vaccine in 1963.

In 2000 measles was declared eliminated from the U.S. This specifically means that while cases may occasionally show up from other highly endemic areas of the world, extended and ongoing transmission of the virus does not occur and outbreaks are quite rare. This success is the result of broadly achieving and sustaining high levels of immunization in children.

There is, however, a risk that measles could again become endemic in this country. Since measles spreads so easily, high immunization levels -- which result in a high degree of population immunity – are required to keep measles out. Experts say communities are only safe from measles outbreaks when the proportion of immune individuals exceeds 95%.

Even before COVID, there were concerns for measles problems. In 2019 the US saw the highest number of measles cases in over 25 years, and the loss of measles elimination status for the country was only narrowly averted. That same year Michigan experienced its worst measles outbreak since 1991.

Over the past year the COVID-19 situation has had the effect of keeping many parents from taking children to their doctor’s office or immunization clinic for routinely recommended vaccinations and other well-child services. Data from the Michigan Care Improvement Registry (MCIR), the state’s immunization database, show a concerning drop in childhood immunization levels since the COVID-19 pandemic began in early 2020. Between April 2020 and April 2021, measles-mumps-rubella (MMR) vaccine rates among Michigan’s two-year-old children, already considered below optimal levels, dropped nearly 4 percentage points, from 84.7% to 80.9%. Rates of the full series of recommended vaccinations for two-year-old children fell from 56.0% to 54.3% in the same period.

Although cases of measles and other vaccine-preventable diseases in the U.S. were lower in 2020 and into 2021, experts believe this to be the result of far less travel, as well as disease mitigation measures for COVD-19 like social distancing and mask-wearing. The concern is that as time goes on and routine activities resume, many cohorts of children will not be adequately protected against vaccine-preventable disease, setting communities up for outbreaks of these diseases that have been successfully held in check.