The number of measles cases reported in the United States this year has continued to grow, and state and local health departments—which are largely responsible for tracking, reporting, and combatting measles outbreaks—are feeling strained.

US measles cases surpass 1,000

CDC on Monday announced local health officials reported 22 new measles cases last week, bringing the total number of measles cases reported so far this year to 1,044 cases as of June 13.

The number of measles cases reported so far this year surpassed the previous 25-year high, when 963 cases were reported in 1994. According to CDC, this year's measles outbreak is on pace to be the United States' worst such outbreak since 1992, when a total of 2,126 cases were reported for the entire year:

According to the latest CDC data, 28 states have reported measles cases as of June 13. CDC researchers noted there currently are measles outbreaks in California, New York, Pennsylvania, and Washington:

Measles is largely preventable with the measles, mumps, and rubella (MMR) vaccine. One dose of the vaccine is 93% effective at preventing measles, and two doses are 97% effective against the disease.

But the disease is highly contagious and requires communities to maintain measles vaccination levels between 93% and 95% to prevent the disease's spread.

The United States could be at risk of losing its World Health Organization designation as a country that has eliminated the disease if the number of U.S. measles cases continues to rise. A country is considered to have eliminated measles after an absence of continuous spread of the disease for more than a year, and the United States in 2000 largely eliminated person-to-person transmission of the measles.

CDC researchers have attributed the high number of measles cases in 2019 to a few large outbreaks in the United States, including one in Washington and two in New York. A large number of the measles outbreaks reported so far in 2019 were associated with close-knit communities where individuals are underimmunized. CDC officials said misinformation about the risks of vaccinations has led to lower vaccination rates in the communities facing outbreaks.

State, local health departments feeling strained

According to the Wall Street Journal, the measles outbreaks and cases are taking a toll on state and local health departments, which are largely responsible for identifying the source of a measles outbreak to determine when and where a patient might have spread the viral infection.

Once health officials have determined the source of an outbreak or measles cases, they notify all known contacts of the infected patient, post notices to warn patients of measles cases, and review security footage and evaluate hospital records to determine who else might have been exposed to the disease. In some cases, health officials offer MMR vaccines to unvaccinated individuals who might have been exposed. The vaccine is effective for up to 72 hours after an individual's exposure to measles, the Journal reports.

New York has seen the highest number of measles cases so far this year when compared with other states, with 588 confirmed cases in New York City and 334 confirmed cases in the rest of the state as of last week, according to the Journal. In response, New York state and city public health officials have been collaborating with community leaders and pediatricians to discuss MMR vaccinations, and county health officials have been administering the MMR vaccine. For example, New York's Rockland County, which has experienced the most measles cases outside of New York City, has administered more than 21,300 doses of the MMR vaccine since the outbreak began.

Karen Smith, director of the California Department of Public Health, explained, "If you have something like a measles outbreak, pretty much everyone in your department is going to be working on that. It really impacts the entire system." According to a recent report by California state Sen. Richard Pan (D), the 44 measles cases that were reported in California from January to May 10 cost the state more than $400,000, which includes the more than $80,000 the state spent to address three cases in which measles patients had visited the Los Angeles International Airport.

Alan Melnick, director of Clark County Public Health in Washington, said county health officials have logged more than 19,000 working hours—which involved reaching out to more than 4,000 individuals for initial interviews and quarantining and monitoring 800 individuals—and spent over $800,000 to suppress the county's measles outbreak. According to the Journal, county public health officials who normally focus on other responsibilities were reassigned to focus on tracking measles cases, which meant the county had to forgo food inspections and other disease tracking efforts. Clark County has not confirmed a new measles case since March 18. Melnick said, "It was kind of a nightmare, in terms of the workload. Public health is underfunded at all levels, and this is $800,000 spent on something completely preventable" (Abbott, Wall Street Journal, 6/16; Kommers, Becker's Clinical Leadership & Infection Control, 6/17; Borter, Reuters, 6/17).