The statement seemed to offer an assurance that other vaccines were not subject to the new restrictions. “Changes regarding seasonal vaccines like COVID and influenza do not change the Department’s policy or messaging regarding childhood immunizations,” it read.
This flu season, the health department has reportedly canceled standard vaccination events and clinics. On social media, the department has avoided mentioning flu shots in posts about the flu, instead advising people to wash their hands and cover their coughs.
While Louisiana is seeing an early surge in influenza, the rest of the country is on an upward trend in what appears to be a normal-looking season so far. Nationally, the percentage of doctor visits that were for ILIs is 3.8 percent, with the upswing in ILI activity similar to what was seen in the 2019–2020 flu season at this point in the year. At the peak of flu seasons, the percentage of visits for ILIs usually tops out around 7 percent to 8 percent.
US ILI activity charted by week across several flu seasons Credit: CDC
Two children died last week of flu, bringing the season’s total pediatric deaths to four. In the 2023–2024 season, 206 children died with influenza-associated disease. Most of the deaths occurred in early 2024.
COVID-19 is also ramping up a winter wave. While standard disease burden indicators—hospitalization and deaths—are low, they’re trending positive. Wastewater surveillance, meanwhile, is showing a steep incline, with levels of the virus being detected at “moderate” levels.
Enlarge/ A US child infected with measles during a 2024 outbreak. The child’s cheek shows the characteristic rash associated with this viral infection.
With one of the highest vaccine exemption rates in the country, Oregon is experiencing its largest measles outbreak in decades. This year’s count is now higher than anything seen since 2000, when the Centers for Disease Control and Prevention declared the highly contagious virus eliminated from the US.
Last month, when the outbreak tally was still in the 20s, health officials noted that it was nearing a state record set in 2019. There were 28 cases that year, which were linked to a large outbreak across the border in Washington state. But, with that record now surpassed, the state is in pre-elimination territory.
“Before 2019, you have to go all the way back to the early 1990s to see case counts this high,” Paul Cieslak, medical director for communicable diseases and immunization at Oregon Health Authority, said in a statement. “The reason is, we maintained very high vaccination rates and very high population levels of immunity. Unfortunately, we’ve seen an erosion in the percentage of people who are getting vaccinated against measles.”
Vaccination decline
In 2000, when measles was declared officially eliminated, only about 1 percent of kindergarteners in the state had exemptions from childhood vaccines, such as measles. But in the years since, Oregon has become one of the states with the highest exemption rates in the country. In the 2022–2023 school year, 8.2 percent of Oregon kindergarteners had exemptions from vaccinations, according to a CDC analysis published in November. Only Idaho had a higher rate, with 12.1 percent of kindergarteners exempt. Utah was a close third, with 8.1 percent, followed by Arizona (7.4 percent) and Wisconsin (7.2 percent).
Oregon’s exemption rate has risen since then, with the exemption rate now at 8.8 percent, according to the Oregon Health Authority. Any exemption rate above 5 percent is concerning. At that threshold, even if every non-exempt child is vaccinated, a state will not be able to achieve the target of 95 percent vaccine coverage expected to prevent sustained transmission of infectious diseases.
Health officials are directly linking the rise of non-medical exemptions to the current measles outbreak, which is centered in Clackamas, Marion, and Multnomah counties. All three are in the northwestern corner of the state, with Clackamas and Multnomah in the Portland area.
“In Clackamas County, as in other Oregon counties, pockets of unvaccinated people raise risk of infection in communities where they live,” Clackamas County Health Officer Sarah Present said. “That’s why the counties reach out to every case that’s been identified and try to determine exactly where they’ve been while infectious.”
Notorious virus
Measles is among the most infectious viruses known. It is notorious for its ability to stay aloft in indoor air for up to two hours after an infected person has been present. For unvaccinated people who are exposed, up to 9 out of 10 will end up falling ill. Those who become infected are contagious from about four days before developing the tell-tale rash and four days after it erupts. Other common symptoms of the infection include high fever, runny nose, cough, and conjunctivitis (pink eye). Many children become severely ill, requiring hospitalization.
In a small percentage of cases, measles can lead to severe complications, including pneumonia, encephalitis, and a progressive neurological disorder (subacute sclerosing panencephalitis), which develops five to 10 years after an initial infection. Additionally, measles is known to cause “immune amnesia.” That is, being infected with measles virus wipes out existing antibodies and immune responses to other germs, leaving people more vulnerable to other diseases.
So far this year, the US has logged 236 measles cases. Of those, 40 percent were in children under the age of 5, while 30 percent were in children and teens between the ages 5 and 19. Eighty-seven percent were either unvaccinated or had an unknown vaccination status. Forty-four percent (103 of 236) were hospitalized.
This year’s tally is already well ahead of the total for 2023, which reached just 59 cases. It is still significantly lower than the 1,274 cases seen in 2019, when the US nearly lost its elimination status.
Enlarge/ A view from a hospital as children receiving medical treatment, in capital Kabul, Afghanistan on April 18, 2022. More than 130 children have died from the measles in Afghanistan since the beginning of this year.
The Centers for Disease Control and Prevention and the American Medical Association sent out separate but similar pleas on Monday for unvaccinated Americans to get vaccinated against the extremely contagious measles virus as vaccination rates have slipped, cases are rising globally and nationally, and the spring-break travel period is beginning.
In the first 12 weeks of 2024, US measles cases have already matched and likely exceeded the case total for all of 2023. According to the CDC, there were 58 measles cases reported from 17 states as of March 14. But media tallies indicate there have been more cases since then, with at least 60 cases now in total, according to CBS News. In 2023, there were 58 cases in 20 states.
“As evident from the confirmed measles cases reported in 17 states so far this year, when individuals are not immunized as a matter of personal preference or misinformation, they put themselves and others at risk of disease—including children too young to be vaccinated, cancer patients, and other immunocompromised people,” AMA President Jesse Ehrenfeld said in a statement urging vaccination Monday.
The latest data indicates that vaccination rates among US kindergarteners have slipped to 93 percent nationally, below the 95 percent target to prevent the spread of the disease. And vaccine exemptions for non-medical reasons have reached an all-time high.
The CDC released a health advisory on Monday also urging measles vaccination. The CDC drove home the point that unvaccinated Americans are largely responsible for importing the virus, and pockets of unvaccinated children in local communities spread it once it’s here. The 58 measles infections that have been reported to the agency so far include cases from seven outbreaks in seven states. Most of the cases are in vaccine-eligible children aged 12 months and older who are unvaccinated. Of the 58 cases, 54 (93 percent) are linked to international travel, and most measles importations are by unvaccinated US residents who travel abroad and bring measles home with them, the CDC flagged.
The situation is likely to worsen as Americans begin spring travel, the CDC suggested. “Many countries, including travel destinations such as Austria, the Philippines, Romania, and the United Kingdom, are experiencing measles outbreaks,” the CDC said. “To prevent measles infection and reduce the risk of community transmission from importation, all US residents traveling internationally, regardless of destination, should be current on their [measles-mumps-rubella (MMR)] vaccinations.” The agency added in a recommendation to parents that “even if not traveling, ensure that children receive all recommended doses of MMR vaccine. Two doses of MMR vaccine provide better protection (97 percent) against measles than one dose (93 percent). Getting MMR vaccine is much safer than getting measles, mumps, or rubella.”
For Americans who are already vaccinated and communities with high vaccination coverage, the risk is low, the CDC noted. “However, pockets of low coverage leave some communities at higher risk for outbreaks.” This, in turn, threatens wider, continuous spread that could overturn the country’s status of having eliminated measles, which was declared in 2000. The US was close to losing its elimination status in 2019 when outbreaks among unvaccinated children drove 1,247 cases across 31 states. Vaccination rates have only fallen since then.
“The reduction in measles vaccination threatens to erase many years of progress as this previously eliminated vaccine-preventable disease returns,” the AMA’s Ehrenfeld warned.
As Ars has reported previously, measles is among the most contagious viruses known and can linger in airspace for up to two hours. Up to 90 percent of unvaccinated people exposed will contract it. Symptoms can include high fever, runny nose, red and watery eyes, and a cough, as well as the hallmark 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.
