This year has been a rollercoaster for public health, with historic firsts, unwelcome comebacks, and rays of hope. Here’s a look back at a few of the significant public health topics we covered in 2024.
The Usual Suspects: COVID and Flu
In our 2023 public health highlights, we noted that experts were forecasting 2024 as a “concerning year” in terms of lots of viruses circulating, and they weren’t wrong: Thanks to suboptimal vaccination rates, the CDC estimates of the 2023–2024 flu season show an increase in numbers of illnesses and deaths from the previous season, and U.S. pediatric deaths for this season (200) have already exceeded the previous high reported for a non-pandemic flu season.
In March, for the first time since 2021, the CDC updated its COVID isolation guidance, just a few months before the rise of the “FLiRT variants” KP.2 and its parent JN.1, which drove a summer surge. The latest COVID vaccines, released in late August, included mRNA vaccines from Moderna and Pfizer and a protein-based vaccine from Novavax. But as with flu vaccines, uptake has so far been low.
H5N1 Avian Influenza Stretched Its Wings
H5N1 has been circulating in wild birds and on poultry farms for years, but it gained greater attention when it was found in dairy cows in March 2024. As of December 18, the virus has been reported in 123,689,426 poultry and on 860 dairy farms.
More than 50 human cases have been confirmed in the U.S., and in October, the virus was found in a pig—spurring concern about its ability to jump species and mutate.
“The good news, so far,” Andrew Pekosz, PhD, professor in Molecular Microbiology and Immunology, said in November, “is that no clear person-to-person transmission of any significant nature has been documented or detected.”
Emerging Consequences of Abortion Bans
Since the 2022 Dobbs decision, women’s health care in the U.S. has faced a new set of challenges. Abortion bans are changing where prospective doctors study and work, for example—and stand to exacerbate health care shortages and disparities.
In January, an analysis of national survey data found an increase in self-reported anxiety and depression symptoms among respondents in states that banned abortion after the 2022 Dobbs decision, while a study published in June found that infant deaths in Texas increased more than expected in the year following the state’s 2021 ban on abortion in early pregnancy.
A Resurgence of Vaccine-Preventable Diseases
In November, the WHO announced that measles outbreaks were occurring in every region of the world. In the U.S., the CDC reported 16 outbreaks of measles (so far) in 2024, compared with four in 2023. The surge is believed to be caused by inadequate vaccination coverage, fueled by the anti-vaccination movement.
Pertussis, too, returned with a vengeance: More than six times as many cases of the highly contagious bacterial infection had been reported in November compared to the same time in 2023. The total number of cases this year is also higher than what was reported at the same time in 2019, pre-COVID.
“We’ve done remarkably well in preventing vaccine-preventable diseases and in achieving high immunization coverage in America. But there are communities throughout the U.S. where vaccine coverage is lower than it needs to be,” said William Moss, MD, MPH, executive director of the International Vaccine Access Center and professor in Epidemiology.
Mpox Became a Global Concern—Again
On August 14, the WHO declared that the outbreaks of mpox (specifically clade Ib) in the Democratic Republic of the Congo and several other countries in Africa constituted a public health emergency.
“There have also been cases identified outside the African continent, for example, in Sweden,” Moss said in November. “It is just a matter of time before we see this clade I of the mpox virus here in the U.S.” (Note: Clade II of mpox has been circulating in the U.S. since the 2022 outbreak.)
The JYNNEOS mpox vaccine is being made available to areas under the emergency, but efforts are still underway to get shots into the arms of those who need them.
Gun Violence: A Crisis and a Conviction
On July 25, U.S. Surgeon General Vivek Murthy, MD, declared firearm violence a public health crisis. Guns also remained the leading cause of death for children and teens.
This year saw something unprecedented, however: The manslaughter convictions of James and Jennifer Crumbley, whose son shot and killed four students at his school. The conviction “has shown a new avenue, a different treatment toward school shootings and accountability,” said Tim Carey, JD, a law and policy adviser at the Johns Hopkins Center for Gun Violence Solutions.
Declines in Overdose Deaths and STIs
CDC data released in December show a drop of almost 17% in drug overdose deaths from 2023. This is believed to be driven in part by the OTC availability of naloxone, as well as increased access to addiction treatment medications and harm-reduction services.
The STI epidemic lost steam in 2023, according to CDC data—with syphilis increasing by only 1% after years of double-digit increases, and gonorrhea cases dropping 7%, falling below pre-COVID levels.
What’s behind the improvement? Experts point to growing use of the antibiotic doxycycline as a “morning-after pill” to reduce the risk of bacterial STIs, as well as changes in sexual behavior and testing habits among high-risk populations after the 2022 mpox outbreak.
The EPA Said No to PFAS
In April, the EPA mandated that water providers reduce per- and poly-fluoroalkyl substances (PFAS)—also known as “forever chemicals”—to near-zero levels.
“There’s increasing evidence that there are toxic effects [of PFAS] on a variety of levels,” said Carsten Prasse, PhD, MSc, assistant professor in Environmental Health and Engineering. The mandate “will hopefully lead to more research to address the presence of these compounds in the environment,” he said.
However, from the Good Neighbor Plan to the Chevron deference, SCOTUS continues to disempower the agency at a time when the U.S. desperately needs better and more informed environmental protections.
Extreme Heat and Weather Disasters
Communities within the U.S. and abroad continued to experience the effects of the escalating climate crisis, including living with extreme heat and suffering the impact of disasters like Hurricane Helene.
A special issue of Hopkins Bloomberg Public Health magazine explored the Earth crisis—and the role we all play in solving it: “Our only way forward requires deep, rapid, structural change in how we live and a global commitment to protecting and regenerating Earth’s natural systems,” wrote Samuel Myers, MD, MPH, director of the Johns Hopkins Institute for Planetary Health.
U.S. Life Expectancy Came Up Short
A new report from the Bloomberg American Health Initiative found that heart disease, overdoses, firearm violence, and motor vehicle crashes—in that order—are responsible for a 2.7-year difference in life expectancy in the U.S. compared with England and Wales.
“There is simply no good reason why people in the U.S. can expect to die nearly three years earlier than their counterparts across the Atlantic,” said Josh Sharfstein, MD, director of the Initiative and vice dean for Public Health Practice and Community Engagement. “If we choose programmatic and policy solutions based on evidence, we will close this gap.”
Looking Ahead to 2025
We’re already asking hard questions: What powers do states have to determine and take action on their own public health priorities? And how will the outcome of the election factor into major health sectors? What is the future of environmental protections in the next administration?
The public health landscape is always changing. But those who work in the field are no strangers to emergencies and surprises, and are determined to keep moving forward.
Morgan Coulson is an editorial associate in the Office of External Affairs at the Johns Hopkins Bloomberg School of Public Health.