In some cases, vaccinated people can transmit measles, finds a review and meta-analysis of 33 reports published late last week in Expert Review of Vaccines.

“Measles transmissions from vaccinated cases, although relatively uncommon, must be considered in public health investigations, as such transmissions can contribute to outbreaks,” wrote the authors, led by researchers at Public Health Ontario. 

A third of disease spreaders had received 2 doses

It’s estimated that measles vaccines have prevented about 94 million deaths from 1974 to 2024. Prior to the vaccine’s introduction, measles caused 2.6 million deaths every year worldwide. 

The two-dose measles shot helped many countries eliminate the fast-spreading respiratory illness. But that trend has been shifting as vaccine hesitancy increases. This year, the United States has seen its most measles cases since 1991. 

For the review, the scientists examined peer-reviewed studies, as well as reports published outside of traditional publishing to understand if those vaccinated against measles might spread the illness to others. Some people can experience secondary vaccine failure, in which a natural, gradual loss of vaccine-created immunity is amplified because there’s little circulating virus to boost the immune response.  

Across all included reports, 70 out of 890 vaccinated people (7.9%) passed measles to others, which caused 237 secondary cases of the illness. Thirty-one percent of the transmitters, 22 people, had received two doses of the measles vaccine. 

Measles transmissions from vaccinated cases, although relatively uncommon, must be considered in public health investigations, as such transmissions can contribute to outbreaks.

The most common symptoms among the 19 transmitters with symptom information were rash (16 people), fever (11) and cough (11). Most vaccinated people who spread measles experienced milder symptoms and a shorter illness than those who weren’t vaccinated. Most often, cough, breathing, or talking likely caused measles to spread. 

Information that links vaccination to healthy aging might encourage more older adults to get recommended immunizations, particularly if they believe doing so benefits their cardiovascular (heart-related) or cognitive (thinking-related) health.

The study, published today in Vaccine, analyzed surveys of 2,416 adults, aged 60 or older, living in Auvergne-Rhône-Alpes, a region in southern France that borders Italy and Switzerland. The questionnaire asked participants whether they agreed with statements, such as "Vaccination helps me age well," and "I get vaccinated to protect my loved ones, my children and grandchildren."

Researchers found that messaging that emphasized how vaccines reduce the risk of stroke and myocardial infarction (heart attacks) generated the highest levels of vaccination interest. Information on the link between dementia prevention and vaccination also showed promise. Messages about falls and fractures appeared least influential.

Perhaps predictably, people who had more of the recommended vaccinations were more likely to agree with these statements. The fewer vaccines people had, the less likely they were to be swayed by this messaging.

Older adults want to stay independent 

The authors note that, unlike infections, cardiovascular events and neurocognitive disorders are among the health outcomes that concern older adults most because of their effects on quality of life and independence. 

At the same time, infectious diseases create economic burdens for individuals and the healthcare system. And, as in other countries, France has suboptimal vaccination coverage among adults. 

Therefore, this finding is encouraging from a public health perspective, write the authors, as it shows that messaging that specifically speaks to a population's needs, motivations, and barriers might encourage higher vaccination rates. 

Chronic wasting disease (CWD) has been found on deer farms in Crawford and Portage counties in Wisconsin, the state’s Department of Agriculture, Trade and Consumer Protection (DATCP) announced over the weekend. 

Both counties had previously reported cases in farm-raised deer, including in a 3-year-old buck in Portage County in October 2025.  

The farms are under quarantine while the DATCP and the US Department of Agriculture complete an epidemiologic investigation. The Crawford County case was in a 2-year-old elk cow, and the case in Portage County was in a 3-year-old deer buck. The department released no further details.

1 in 5 state deer farms have reported cases

A total of 231 deer farms, including 52 hunting ranches, are registered in Wisconsin. From 2001 to October 2024, CWD cases were reported on 46 deer farms (20%), and 24 herds were culled as a result. As of October 2025, 17 hunting ranches and seven deer farms that had reported CWD were still in operation, while 22 had closed.

Of the 231 total deer farms, 78 are enrolled in the state’s voluntary CWD Herd Status program, which requires CWD testing of deer 1 year and older, record-keeping, and reporting. Enrollment is mandated for farms that want to move live farm-raised deer within or outside of Wisconsin.

CWD has infected wild deer in most Wisconsin counties. The fatal neurologic disease affects cervids such as deer, moose, and elk. It’s caused by misfolded proteins called prions, which spread through infected body fluids and environmental contamination. It causes symptoms such as discoordination, weight loss, and excessive drooling.

While CWD is not known to affect people, health authorities recommend against eating the meat of infected or sick cervids and urge caution when handling their carcasses.