Mass shootings outnumber annual days in U.S., children are missing school due to measles, Covid-19 is peeping around the corner, and some hope

The Dose (December 15)

Holiday lights are up, and Hanukkah has begun, but man, it’s hard to hold onto cheer as the world delivers blow after blow. This week brings outbreaks of once-forgotten diseases, rising respiratory illness, and more mass shootings. All underscoring how fragile health and safety really are, and how much suffering can be prevented. Still, I deeply believe that connection, hope, and small, deliberate actions remain powerful ways—at times the only ways—to protect one another and keep one foot moving in front of the next.

Here’s The Dose to start your week.

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Mass shootings continue to outnumber days in the U.S.

I tried to put into words last night the evidence-based solutions to mass shootings. I was initially trained as a violence epidemiologist, am married to a police officer, and am a mom, and I know there are things we can do as a society. Then I deleted it. Then I rewrote it. Then I was just mad about the whole situation and stopped.

It’s hard to put into words the toll this takes on our communities. And it makes it even harder when it happens over and over and over again.

This time, tragedy struck Brown University during finals prep, a time meant for focus, hope, and growth. Students, faculty, first responders, and many of my friends—some who were working the emergency department or were on campus with students—are left in shock and grief, trying to make sense of yet another traumatic event.

As of December 14, the U.S. has had 391 mass shootings—more than the number of days in the year—for the seventh consecutive year. Seventy-five of these occurred at schools. The frequency is high enough that epidemiologists can now identify patterns. The timing of the shooting at Brown follows a familiar one: school shootings often cluster around periods of transition to and from school breaks.

Across the world, another mass shooting tragedy hit Australia, where people celebrating the first night of Hanukkah were likely violently targeted for their beliefs. The horror of losing loved ones at a gathering meant for reflection and celebration is unimaginable.

Almost immediately, social media seized on the tragedy to argue that Australia’s strict gun laws don’t work. I’ll stop that right there. This isn’t a debate because the data are crystal clear:

1. Mass shootings are extremely rare in Australia. Since the Port Arthur massacre in 1996, strict firearm regulations (a buyback program and tight licensing) have kept mass shootings to zero or one per year on average in Australia. By contrast, the U.S. experiences roughly 400–650 mass shootings annually, with more than 46,000 deaths from gun violence each year. As the graph below shows, it’s not even close.

   

2. A tragedy does not disprove the effectiveness of these laws. Data show that strict regulations reduce deaths. Beyond Australia, places like the U.K., Japan, and Canada have similarly strict gun laws and extremely low rates of mass shootings. We can also see variability within the United States. States with the most lax gun laws have the highest rates of gun violence.

3. Firearm deaths are the leading cause of death for children in the U.S., whereas in Australia, child deaths from firearms are extremely rare, with suicide and road accidents being the top causes.

While every loss of life is devastating and mourned, the scale of firearm deaths in the U.S. makes clear that the problem is far from isolated. It is systemic and ongoing. It doesn’t have to be this way. Public support for stronger gun laws is high. Polls consistently show that a large majority of Americans back measures such as universal background checks, restrictions on high-capacity magazines, and mandatory waiting periods.

What this means for you: Please donate blood. For those looking for immediate resources for helping children and youth, the National Child Traumatic Stress Network developed the following fantastic resources:

• Talking to Children about the Shooting (En Español)

• Helping Youth After Community Trauma: Tips for Educators (En Español)

Below are previous YLE posts that are as relevant today as they were before. I hope they help you feel empowered. There are solutions and paths forward.

• We can reduce gun violence in the U.S.—we’ve done hard public health things before.

• It’s hard to explain (and fix) evil—but it’s not mental illness. Focusing solely on it largely avoids confronting the real, more complicated causes.

• Firearms: What you can do right now—there’s a lot.

• Epidemiology of mass shootings—you’ll notice these tragedies follow some, but not all, patterns of previous school mass shootings.

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Infectious disease “weather” report

It’s officially respiratory season: the percentage of physician visits chalked up to coughs, fevers, and sore throats—also called influenza-like illness (ILI)—has passed 3% and continues to rise quickly.

Right now, rates are uneven across the country: some states remain green, reflecting minimal activity, while others are already lighting up red, signaling high levels. Before long, the entire map will be red and purple.

Influenza-like illnesses (ILI). Source: CDC; Annotated by Your Local Epidemiologist

For flu, specifically, we’re seeing this increase first among younger populations, especially school-aged children. Soon these illnesses will spread to older adults as well. CDC estimates there have already been at least 2.9 million illnesses this year and 30,000 hospitalizations. By the end of the season, we can expect roughly 15% of Americans to get the flu.

Tragically, the first pediatric flu death was reported for the 2025-2026 season. I expect many more, given that flu vaccination rates are the lowest they’ve been in decades. Since 2004, we’ve seen an increase in the number of deaths year over year. Last year was a record year for pediatric deaths. Most children who died were not vaccinated.

Covid-19 remains low nationally, but it doesn’t look like this will continue for long. Cases in the Northeast and Midwest are increasing quickly. The South is inching upwards as well. (See your local wastewater trends here.)

Covid-19 wastewater trends by region. Source: CDC; Annotated by YLE

We’ll see where this takes us, but given that we had a mild Covid-19 winter and summer, there are a lot of people out there susceptible to infection. Trends are still hard to predict, given this is a relatively new virus: we could see a large wave or smaller and smaller waves, with Covid-19 becoming the common cold. Time will tell.

What this means for you: All of these trends will only intensify with holiday gatherings, as mixing of households and social networks creates more pathways for viruses to travel. Wearing a mask in crowded indoor spaces helps reduce disruptions in your life. Testing is useful, though for mild illness, it rarely matters which virus you have—except for high-risk individuals, for whom results could guide antiviral treatment. Stay home until symptoms improve to protect others and prevent further spread.

Measles outbreaks continue to march on with 1,926 cases this year. Word on the street is that the U.S. will also lose the WHO measles elimination status early next year.

Two outbreaks continue to grow quickly:

• South Carolina: This outbreak is growing exponentially, with Spartanburg County remaining the epicenter with 126 cases. Fifteen new cases were reported last week, mostly household transmission. Currently, 254 children are in quarantine at 11 schools, missing 21 days of school for an easily preventable disease.

Source: Yale School of Public Health

• Utah/Arizona: 291 cases with ongoing transmission spreading through Utah and Mohave County, Arizona.

What this means for you: If you’re near a measles outbreak, follow guidance from your local public health department. Children under 12 months can get MMR as early as 6 months old, and families up to date on vaccinations are protected.

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Alright, I need some hope… and help.

Simply making it through this year is an accomplishment. Still, even through the fog, there have been wins and moments of good news, and I truly believe we need to hold onto them to keep hope and joy alive.

Every year, I collect public health victories to mark the close of the year, and I’m not stopping now. I’d love your help. What’s your favorite piece of public health good news or biggest win this year? It can be local, national, or global. Share it in the comments, and I’ll try to include some in the final 2025 accomplishments report.

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Bottom line

This week, as respiratory illnesses rise and outbreaks continue, and as our communities are shaken by yet more mass shootings, taking small but meaningful actions—masking in crowds, staying home when sick, staying up to date on vaccines, and advocating for safer environments—can help protect the people we care about.

Love, YLE

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Your Local Epidemiologist (YLE) is founded and operated by Dr. Katelyn Jetelina, MPH PhD—an epidemiologist, wife, and mom of two little girls. YLE reaches more than 425,000 people in over 132 countries with one goal: “Translate” the ever-evolving public health science so that people will be well-equipped to make evidence-based decisions. This newsletter is free to everyone, thanks to the generous support of fellow YLE community members. To support the effort, subscribe or upgrade below: