International health agencies are raising the alarm over a surge in measles and a decline in vaccination rates against the deadly - and preventable - virus.
In the past year, more than 10million people have contracted measles, rising from 8.6million in 2022, according to a joint report from the CDC and World Health Organization.
At the same time, the report found vaccine rates remained low, following a major plummet in 2021.
Measles, which usually causes rash, cough and high fever, can quickly escalate to severe symptoms in one in five unvaccinated people - leading to pneumonia, brain swelling and death.
In 2023, the virus caused 107,500 deaths, mostly in children under five, since children, whose immune systems are fragile, are particularly in danger when infected with the disease.
Since the Covid pandemic, the number of people skipping vaccinations has been increasing. The new report found only 83 percent of people worldwide in 2023 got the measles vaccine - mostly unchanged from a record low in 2021.
Experts suggest this has to do with people missing doctors appointments during Covid, and because of increased vaccine hesitancy, in part promoted by major figures like Robert F Kennedy Jr - the newly nominated head of the Department of Health and Human Services.
In response to this trend, and the increase of measles, WHO and CDC officials reiterated the best way to prevent the disease is through vaccination.
WHO Director-General Dr Tedros Adhanom Ghebreyesus, said: 'Measles vaccine has saved more lives than any other vaccine in the past 50 years'.
Measles in children can look like other skin rashes. The majority of the people who died from measles in 2023 were under five years old
RFK Jr is set to head up the Department of Health and Human Services in Donald Trump's second term as president. The lawyer has made claims that fluoride found in tap water is toxic and promoted the idea that an herbicide called atrazine can cause people to have 'sexual confusion' and 'gender confusion'
In 2000, measles was declared eradicated in the US, following a decades long vaccination campaign that began in 1978.
Other countries in the six regions the WHO covers pledged to make similar gains through vaccinating their citizens- aiming to get 95 percent of them vaccinated.
This 95 percent standard is the goal for herd immunity - representing the number of the populous that needs to get vaccinated in order to stop the spread of an infectious disease.
But the US, and other countries like the UK and Australia, have slipped from that goal, and now outbreaks are occurring worldwide, according to the new report.
The WHO and CDC arrived at their conclusions by processing data from vaccine programs and measles outbreaks in 149 different countries.
The report found the number of countries experiencing large-scale outbreaks increased from 36 to 57.
Almost half of these outbreaks occurred in Africa.
Additionally, between 2000 and 2019, the amount of people who got a measles vaccine went from 71 percent to 86 percent.
The report found progress dropped off in 2021, thanks to the pandemic. Only about 81 percent of people got the measles vaccine in 2021, the lowest rate since 2008.
Public health officials hoped that drop off was a blip, but the 2023 report shows the trend is sticking around.
Now, only 83 percent of the global population has gotten the vaccine. In the US specifically, rates are a bit higher - but still below the federal target, with 92.7 percent of kindergarteners vaccinated.
The number of people dying from the disease has gone down slightly - from 116,800 in 2022 to 107,500 in 2023. This occurred because many of the new cases of the disease occurred in countries with otherwise strong healthcare systems, where children are less likely to die from infectious disease overall, according to the Hill.
The CDC has estimated in the 21st century, 60million lives have been saved by the vaccine.
Despite these positives, the anti-vaxx movement seems to be gaining momentum in recent years.
This could be in part because pandemic vaccine mandates may have led more people to vaccine hesitancy, Dr Anthony Fauci, the former director of the National Institute of Allergy and Infectious Diseases said.
Dr Fauci told the New York Times Americans may have felt like their liberties were infringed on when they were told they had to get a vaccine, unintentionally creating distrust in the healthcare system.
The CDC estimated the measles vaccine has saved 60million lives since 2000. Doctors recommend children get their first MMR vaccine between 12 and 15 months old
He said: 'Man, I think, almost paradoxically, you had people who were on the fence about getting vaccinated thinking, why are they forcing me to do this?'
This hesitancy has been capitalized on by anti-vaccine advocates like RFK Jr, who has become popular for supporting a number of conspiratorial healthcare movements.
He's raged against tap water, both for debunked claims that fluoride is neurotoxic and that chemicals in the supply could turn children transgender.
He has suggested that AIDS is not caused by the HIV virus, that the food industry is committing 'mass poisoning' and that vaccines cause autism.
These claims have struck a chord with many Americans, and experts suggest RFK Jr's arguments have helped re-popularized the anti-vaxx movement.
For the WHO and CDC doctors who released the report, emphasizing the safety and effectiveness of vaccines therefore seemed paramount.
Dr Ghebreyesus added: 'To save even more lives and stop this deadly virus from harming the most vulnerable, we must invest in immunization for every person, no matter where they live.'
Doctors recommend children receive two doses of the measles, mumps and rubella vaccine - with the first one around 12 to 15 months old and the second one around four to six years old.
It's crucial for people to get it at this age to avoid spreading deadly disease to babies whose immune systems are too fragile to protect against the illness.
Injecting a strain of damaged virus into your body, which doesn't make the person sick, trains the immune system to recognize the invader so that it can fight back against it in the future to prevent sickness, according to Cleveland Clinic.
The vaccine works against measles, mumps and rubella viruses because doctors designed it to contain components of all three viruses.
Cold-like symptoms, such as a fever, cough and a runny or blocked nose, are usually the first signal of measles
In recent years, there's also been upticks in mumps and rubella.
In 2024 in the US, there have been 277 cases of measles, with 89 percent of those in unvaccinated people, the CDC reported.
Getting two doses of the MMR vaccine is about 97 percent effective at preventing the disease. In the rare case that a vaccinated person catches the disease, they're less likely to become severely ill with it than unvaccinated people.
Early, and common, signs of measles include fever, dry cough, runny nose, sore throat, inflamed eyes and white spots in the throat.
In the rare case that someone becomes more severely ill with measles, symptoms progress to pneumonia, encephalitis, bronchitis, diarrhea and vomiting. Any of these symptoms can lead to hospitalization, and in the worst cases, death.
According to the CDC, about one in five unvaccinated Americans who get the virus are hospitalized with the condition.
There are no specific treatments for the virus, according to the National Foundation for Infectious Diseases. If someone is hospitalized, they may be given vitamin A to support their immune system and help them get over the virus more quickly.
Since their is no treatment for the disease, doctors urge vaccination, which can prevent serious illness, is the best course.
According to the National Foundation for Infectious Diseases: 'If you are not sure whether you have been vaccinated, it is safe to get another measles vaccine. The only people who should not get measles vaccine are those who are immunocompromised or pregnant.'