Pennsylvania’s measles outbreak exposes the danger of forgetting the disease

Retired doctors warn that decades without widespread measles have weakened public understanding of the infection’s risks as Pennsylvania records more than 1,100 cases and six deaths.

Two retired Pennsylvania doctors say the state’s current measles outbreak is being made worse by a kind of collective forgetting: because the disease was virtually eliminated in the US for so long, many families and even younger clinicians have little memory of how dangerous it can be.

Duncan MacLean, a retired family and geriatric medicine doctor, and Thomas Overholt, who practised paediatrics and internal medicine before retiring, told LebTown that the long success of the measles vaccine may now be working against public understanding. Overholt said there is “no community memory of this disease”, adding that people are now more likely to know someone who had concerns about the vaccine than someone who lost a child to measles or suffered lasting complications from it.

The warning comes as Pennsylvania leads the nation in measles cases, with state health officials reporting 1,136 confirmed infections as of October 9, along with six measles-associated deaths and 219 hospitalisations. The Department of Health said the outbreak spans 39 counties and is the largest the state has seen in more than three decades. Lancaster County has recorded the most cases, while Lebanon County has also been affected.

Before the measles vaccine became widely used in 1963, the disease caused about 50,000 hospitalisations and as many as 500 deaths each year in the United States. The Centers for Disease Control and Prevention declared measles eliminated domestically in 2000, meaning there was no continuous spread within the country, though imported cases still appeared from time to time. That changed in April, when the present outbreak began. Overholt said the return of a disease that had been absent for so long “should … alarm everybody that we now have it again.”

Doctors say the virus remains dangerous because it spreads easily through the air and can linger on surfaces or in the air for hours after an infected person leaves. Symptoms may not appear for up to three weeks, allowing someone to pass the infection on before realising they are ill. Young children, older adults and pregnant women face the greatest risk of complications, including pneumonia, brain inflammation and death.

MacLean said the outbreak underscores the importance of maintaining high vaccination coverage. He said public health experts generally regard 95% immunisation as the level needed for herd immunity, meaning the point at which transmission is difficult to sustain. Based on his review of Pennsylvania Health Department data, he said Lebanon County schools overall appear to fall just below that threshold, with some districts well above it and others well below it. He noted that the available dataset does not cover every grade or every school, but still shows clear differences across the county.

The doctors also pushed back against the idea that natural infection is preferable to vaccination. Overholt said some children who appear to catch measles after a shot may actually have been exposed before the vaccine had time to work, since the MMR vaccine can take about two weeks to build protection. He said immunity from infection is not worth the risk because “in order to get the wild type immunity, you have to get the disease, and some kids don’t, and they can get sacrificed.”

Both doctors also rejected claims linking the MMR vaccine to autism. LebTown reported that they pointed to a study of more than 2.5 million children under 2 that found no connection. Overholt added that rubella, one of the diseases covered by the combined vaccine, can cause severe birth defects, including heart disease and deafness, making prevention especially important.

For parents who are hesitant, MacLean said confrontation is less effective than listening. He said he would begin by asking what concerns they had and where those concerns came from, whether from personal experience, something they heard or material they found online. From there, he would try to understand how strongly they felt before addressing the specific worries driving their reluctance.