In another sign of growing vaccine hesitancy, a new report finds that the percentage of US toddlers vaccinated on time against measles, mumps and rubella (MMR) has fallen since the pandemic.

The percentage of 2-year-olds given the MMR vaccine fell from 80% in 2021 to 77% in 2024, according to a study published today in JAMA Network Open. The new study included nearly 322,000 children with regular access to care.

The researchers found that the strongest predictor of missing the MMR shot by age 2 was late administration of the vaccines recommended for babies at 2 months and 4 months of age.

The American Academy of Pediatrics recommends giving children a first dose of MMR vaccine at 12 to 15 months of age and a second dose at 4 to 6 years. Research shows that at least 95% of children need to receive both doses on time to keep measles from spreading.

Reduced vaccination levels have helped fuel ongoing measles outbreaks across the United States that affected more than 2,000 people in 2025. Two Texas children died after contracting measles last year.

The ninth known case of welder’s anthrax, and the first clinical use of the monoclonal antibody medication obiltoxaximab to treat it, was recently documented in Louisiana. 

An account of the case, published in the most recent Morbidity and Mortality Weekly Report from the US Centers for Disease Control and Prevention (CDC), marks a significant development in the treatment of an often-fatal condition that can afflict metalworkers in the southern United States.

Welder’s anthrax is a type of pneumonia caused by anthrax toxin–producing Bacillus cereus bacteria, a pathogen closely related to Bacillus anthracis. Six of the previous eight documented US cases have been fatal. Risk factors are not well understood but likely include exposure to dust and welding fumes, poor ventilation, and minimal use of personal protective equipment (PPE).

Rapid improvement within days

In September 2024, an otherwise healthy 18-year-old welding apprentice in Louisiana developed severe pneumonia and respiratory failure requiring intubation and mechanical ventilation. The patient had worked as a welder for 6 months immediately preceding his illness and had no history of vaping, smoking, or excessive alcohol consumption. 

The Louisiana Department of Health and the CDC confirmed the presence of anthrax toxin genes in the patient’s blood and in samples from the patient’s worksite. 

The patient received treatment with the recommended multidrug antimicrobial therapy, drainage of a pleural effusion, and obiltoxaximab, which was sourced from the US Strategic National Stockpile and administered 34 hours after welder’s anthrax was suspected (approximately 1 week after symptom onset).

Within days, the patient showed rapid improvement, and mechanical ventilation was discontinued. He was discharged after 26 days; symptoms had resolved by 3-month follow-up. This case study underscores the potential benefits of antitoxin therapy alongside standard antimicrobial treatment for welder’s anthrax, the authors said. 

“To help prevent infections, employers of welders and metalworkers can follow best practices to minimize workplace exposure to welding fumes and gases, as well as soil and dust exposure in worksite areas where the bacteria might be present,” the report notes. “Ongoing study and analysis of environmental, occupational, and host factors associated with welder’s anthrax are needed to identify causes that can guide development and implementation of definitive prevention and control measures.”

• An outbreak of an undetermined gastrointestinal illness sickened 95 passengers and nine crew members on the Celebrity Eclipse cruise ship during a voyage December 20 to 28, according to the US Centers for Disease Control and Prevention’s (CDC’s) Vessel Sanitation Program. A total of 3,042 passengers and 1,235 crew were on board. The main symptoms were vomiting, diarrhea, and abdominal cramps. The CDC noted that norovirus is a common cause of gastrointestinal illnesses on cruise ships, but in this case, the notification occurred after the voyage, when samples were no longer available for testing. The Eclipse sails the Caribbean in December.
• Despite it being summer in Australia, the influenza season is still going strong more than 3 months after it should have ended, virologist Ian Mackay, PhD, adjunct associate professor at the University of Queensland, said on his Virology Down Under blog. Cases stopped declining in October and started to rise again in November, driven by the newly emerged influenza A H3N2 subclade K. The subclade is currently causing outbreaks in the Northern Hemisphere, but whether it will cause a protracted flu season here is unknown.
• Earlier this week, the US Department of Agriculture (USDA)’s Animal and Plant Health Inspection Service (APHIS) documented an outbreak of highly pathogenic avian influenza on a Butler County, Nebraska, layer farm with 144,600 birds.
• This week, the Global Polio Eradication Initiative (GPEI) documented one new case of circulating vaccine-derived poliovirus type 2 (cVDPV2) in Lower Juba, Somalia, with an onset of paralysis on November 15, for a 2025 total of two.