A team of health experts from the Centers for Disease Control and Prevention arrived in Chicago on Tuesday as officials identified three new measles cases amid a flare-up of cases at a migrant shelter in the city's Pilsen neighborhood.
So far, there have been seven cases identified at the Halsted Street shelter. In addition to the three cases identified today, there were two young children, one recovered and one hospitalized in good condition as of March 10, and according to an announcement on Monday, March 11, two adults who were reported in good condition.
The seven cases come just days after the city's health department announced a measles case in a Chicago resident with no recent travel outside of the city and no reported connection with the shelter. The case, announced on March 7, was the first measles case identified in the city since 2019, officials noted. It remains unclear how that resident contracted the highly infectious virus, though the health department noted that the person had been in contact with domestic and international travelers. The person was said to be recovering well at home, and their infectious period ended on March 6.
The measles cases at the shelter have led to a massive response—and strong encouragement from health officials for vaccination. The city's health department on Monday reported that, along with help from other area health officials and health care providers, it had "successfully vaccinated more than 900 shelter residents with the measles-mumps-rubella (MMR) vaccine." Those newly vaccinated shelter residents are to stay at the shelter for 21 days until their immunity from the vaccination reaches full effectiveness. Meanwhile, more than 700 shelter residents, who had been assessed and found to already have immunity to measles from either prior vaccination or infection, were allowed to move freely in and out.
AdvertisementIn a statement Monday, the city's health commissioner Olusimbo "Simbo" Ige called the response a "massive operation." She thanked health partners and shelter residents for "understanding the need to get vaccinated and quarantine. ... Vaccination remains by far the most effective way to prevent the spread of measles. New arrivals and all Chicagoans should get the MMR vaccine if they haven’t already."
Contrast with Florida
Chicago's proactive response, full-throated calls for vaccination, and collaboration with the CDC are in contrast to the approach Florida's health department took in a recent measles outbreak. That outbreak began last month in a Broward County elementary school with a vaccination rate reported to be below the target of 95 percent. To date, Broward has reported nine measles cases, all in children. However, the health department has not released data on if or how all nine cases are connected to the school, nor has it reported the vaccination status of those cases.
During the initial response, Florida's health department went against CDC guidance and did not have unvaccinated children stay home during their potential infectious period after exposure to the highly infectious virus. In a February 20 letter sent to parents of the elementary school's students, Florida Surgeon General Joseph Ladapo—who is known for spreading anti-vaccine rhetoric and vaccine misinformation—told parents that the health department would leave it up to parents to decide if their children should attend school.
Though the letter notes that two MMR vaccines are about 97 percent effective at preventing a measles infection, it noticeably does not recommend vaccination or urge parents to immunize children who are currently unvaccinated. This also contradicts CDC guidance. In fact, the agency provides a letter template for this exact situation: a letter intended to be sent to parents in the event of school exposure to measles. In the template, the CDC writes: "If your child is not in compliance with the MMR requirements, they should receive a dose of MMR vaccine, unless there is a medical reason why they cannot receive the vaccine. MMR vaccine is effective and safe."
The Florida health department has declined multiple times to respond to Ars' questions about its response to the measles outbreak, including why the department does not explicitly recommend vaccination or follow CDC guidance.
Measles threat
The contrasting responses in Chicago and Florida could be critical this year as the country faces a continued threat of measles resurgence. Already this year, the US has tallied at least 45 measles cases in 17 states. In all of 2023, the US saw 58 cases. In January, the CDC urged health care providers to "be on alert" for measles. The relatively high tally so far is linked to two significant factors: a rise in measles globally as routine vaccination stalled during the COVID-19 pandemic and slipping rates of childhood vaccination coverage in the US amid the spread of anti-vaccine rhetoric.
In December, the World Health Organization described the rise in measles as "alarming," reporting a more than 30-fold increase in measles cases in the European Region from 2022 to 2023. A month before that, the CDC released a study finding that vaccination rates among US kindergartners continue to be below the 95 percent target at 93 percent. Additionally, in 2023, non-medical exemptions hit an all-time high and, in some states, exemption rates were so high that states would not be able to reach the 95 percent target for preventing the spread of infectious diseases even if all non-exempt children were vaccinated.
AdvertisementMeasles was declared "eliminated" in the US in 2000—meaning travel-related cases arise but the virus does not spread continuously in the country. But that status is under threat by the growing pockets of unvaccinated or under-vaccinated children around the country. In 2019, the US nearly lost its elimination status amid a massive and long-term outbreak in New York. That year, the country tallied 1,247 cases across 31 states.
Before vaccines became widely used in the US, the CDC estimates that 3–4 million people in the US were infected each year, sending 48,000 to the hospital, causing brain swelling in 1,000, and killing 400 to 500 people.
Now, measles is relatively rare but still dangerous to those unvaccinated. The virus is among the most contagious germs on earth and can linger in airspace for up to two hours. Up to 90 percent of unvaccinated people exposed to the virus will contract it. Symptoms can include high fever, runny nose, red and watery eyes, and a cough, as well as the telltale rash. About 1 in 5 unvaccinated people with measles are hospitalized, while 1 in 20 infected children develop pneumonia, and up to 3 in 1,000 children die of the infection. Brain swelling (encephalitis) can occur in 1 in 1,000 children, which can lead to hearing loss and intellectual disabilities. The virus can also destroy immune responses to previous infections—a phenomenon known as "immune amnesia"—which can leave children vulnerable to various other infections for years afterward.
This post was updated to include the three additional cases identified Tuesday.
