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May 14, 2025 LDH concludes measles investigation, updates whooping cough cases in LouisianaNo new measles cases identified
Baton Rouge, Louisiana, - The Louisiana Department of Health (LDH) today announced encouraging news regarding measles in the state, with no new infections identified following two recently reported cases. Yet, LDH continues to monitor a concerning trend of increasing whooping cough (pertussis) cases across Louisiana.
Measles
LDH initially announced the measles cases, which were related, in adult residents of Region 1 (Jefferson, Orleans, Plaquemines, and St. Bernard parishes) in April and concluded its epidemiological investigation on May 9. One of the confirmed cases was linked to international travel, and neither of the individuals required hospitalization. The first patient was unvaccinated, and the vaccination status of the second patient is unknown.
No additional cases were identified from the LDH Office of Public Health’s (OPH) epidemiology team's extensive public health investigation, in which the team identified and notified healthcare and community contacts of their potential exposure to measles and monitored their health.
The last endemic case of measles in Louisiana was in 1996. Since then, Louisiana has recorded one case in 2008, two in 2018, three in 2024, and two in 2025. No deaths were reported during that period.
Measles is a highly contagious vaccine-preventable respiratory virus that can spread rapidly among individuals who have not received the measles, mumps, rubella (MMR) vaccine, leading to rapid outbreaks. Severe cases can result in hospitalization and, in extreme cases, can lead to death. The measles virus can be especially dangerous for babies and young children.
The most effective way to prevent measles is through immunization. Two doses of the MMR vaccine are highly effective at preventing measles. Talk to your healthcare provider about whether the MMR vaccine is right for you.
Whooping cough
Since its last update on May 2, the Office of Public Health (OPH) has identified six more whooping cough cases in Louisiana, bringing the total cases in 2025 to 170.
The 170 whooping cough cases in 2025 have already surpassed the entirety of 2024, when 154 cases were reported. Louisiana is on track to set a record high in 2025, exceeding the previous record of 214 cases reported in 2013.
The substantial increase in whooping cough in Louisiana has caused a corresponding rise in hospitalizations and deaths. Since September 2024, 42 people have been hospitalized, with 69% among babies younger than 1 year old. Sadly, two young infants hospitalized with whooping cough have died within the last year. These are the first whooping cough deaths reported in Louisiana since 2018.
Whooping cough is a highly contagious, vaccine-preventable respiratory illness caused by the bacterium Bordetella pertussis, with predictable increases in reported cases every few years. It spreads from person to person through coughing, sneezing, and close contact. People infected with whooping cough can spread the bacteria from the start of symptoms and for up to three weeks after coughing begins.
Whooping cough can occur in anyone. However, infants younger than 1 year old are most affected, showing the highest reported rates of infection and the greatest likelihood of severe complications and death. The bacteria that cause whooping cough are often unknowingly spread to infants by close family or caregivers.
Vaccination is the best way to prevent serious complications. The vaccines are safe and effective, but protection fades over time. Two vaccines help protect against whooping cough: DTaP for children younger than 7 years and Tdap for older children, teens, and adults. Both vaccines also protect against tetanus and diphtheria.
LDH resources