Fortified tortillas, affordable insulin, and flu treatments
The CA Dose, January 15, 2026
As we launch into 2026, two new California policies could have important health impacts: fortifying foods to prevent birth defects, and making insulin more affordable. And as flu continues to surge, there’s news for treatment and vaccines. Let’s start with food.
Fortifying tortillas for healthy babies
Beginning January 1, corn masa flour sold in California will be fortified with vitamin B9 (folic acid)—meaning tortillas, chips, and other staples made from masa will now contain a nutrient that reduces the risk of serious birth defects. This is a quiet change that can have huge benefits for Californians.
What is folic acid and why does it matter? Folic acid is the synthetic form of vitamin B9 (folate). While folate is naturally found in foods like dark green leafy vegetables, folic acid is more commonly used as a supplement to fortify foods.
One of its most important roles is as a building block for the “neural tube”—the earliest form of the brain and nervous system, formed during embryonic development before people even know they’re pregnant. This is why adequate intake before and early in pregnancy reduces the risk of neurologic birth defects like spina bifida.
In 1998, the U.S. mandated that wheat flour be fortified with folic acid, leading to a 35% drop nationally in neural tube birth defects. But not all communities benefited to the same degree.
Why focus on masa? Corn masa—a staple food for many Latino families—was left out of the federal plan to fortify flour. Only about a quarter of Hispanic women in California report taking any folic acid daily in the month before pregnancy, compared with almost half of non-Hispanic white or Asian women.
At the same time, neural tube defects are more than twice as common among infants born to Hispanic mothers in California—about 7.1 per 10,000 live births, compared with 3.2 per 10,000 among non-Hispanic white mothers. Adding folate to masa is meant to help close this gap.
Genetic variations. Some people have genetic differences that make the body use folate more slowly than usual. Variants in the MTHFR gene, found in up to half of the population, can influence folate metabolism. This has been well researched, and the evidence is clear that people with MTHFR gene variants can process all types of folate, including folic acid. In fact, folic acid is the only type of folate shown to help prevent neural tube defects.
Prevention in action. What makes this policy so powerful is how little it asks of people. No appointments. No new programs to enroll in. No special vitamins to remember to buy at exactly the right time.
Instead, this builds protection directly into a commonly eaten food, reaching people before pregnancy is recognized. This reflects a core lesson of public health: the most effective prevention strategies don’t depend on individual behavior or require out-of-pocket costs.
This measure has support across both sides of the aisle. Alabama’s version of the law takes effect in June, and lawmakers in Florida, Georgia, and Oklahoma are considering similar legislation.
Many Californians will never notice this change. But fewer families will have to experience preventable birth defects because of it. That’s what success looks like in prevention—quiet, evidence-based, and equitable.
California’s insulin innovation
For many people living with diabetes, insulin is a life sustaining medicine—but it can be expensive. As of January 1, insulin has become significantly more affordable in California.
Through CalRx, the state’s drug purchasing and manufacturing initiative, some forms of insulin are being offered at more than five times below usual market prices. This is important for two reasons: it increases access to life-sustaining medication for people with diabetes, and it models how government can innovate to make drugs affordable.
Building on the success of naloxone. Insulin is the second medicine CalRx has focused on. The program was founded in 2024 to increase access to naloxone, a medication that can reverse an opioid overdose. As Health Officer in Marin County at the time, I saw CalRx as a lifesaver—literally. By lowering prices, our county was able to supply vending machines with free naloxone for people at highest risk. Expanded access to naloxone helped contribute to a decline in overdose deaths in California.
Why insulin? About 3.3 million California adults—roughly one in nine of us—live with diabetes. Everyone with type 1 diabetes requires insulin, and many with type 2 diabetes eventually do as well. Diabetes disproportionately affects people with lower incomes, making affordability even more important. When insulin costs too much, people are forced to choose between medication or other essentials like food, rent, and utilities.
Nationally, about one in five insulin users reports rationing doses because of cost. Skipping insulin doses is dangerous and contributes to diabetic emergencies, hospitalizations, and preventable deaths. For patients facing cash prices of up to $250–$300 for a pack of insulin glargine pens, CalRx’s $55 option can translate into thousands of dollars in annual savings for people who are uninsured, underinsured, or have high deductibles.
California is well positioned to use this kind of approach, thanks to a strong biotechnology and manufacturing base, purchasing power, and willingness to step in when national systems fall short.
What this means for you: If you take insulin and have any out of pocket costs, talk to your doctor. Drugs produced through CalRx are intended to be available to all Californians with a prescription. You don’t have to apply, and there are no eligibility requirements.
If you don’t use insulin, you’ll still benefit—better access to medication fro people wth diabetes can reduce emergency department visits, hospitalizations, and long-term health costs statewide.
The next challenge. This spring CalRx will begin offering albuterol for schools, to ensure children with asthma have access to inhalers when they need them at school.
Public health innovation isn’t always about discovering something new. Sometimes it’s about reshaping systems so people can reliably access the basics.
Infectious disease “weather report”
Flu
We’re in the thick of flu season in California. Wastewater levels, cases, emergency department visits, and hospitalizations are increasing. With the surge in cases there’s increased demand for treatments. It’s a good time for a refresher on flu antivirals like Tamiflu or Xofluza.
Antiviral medications. Not everyone with the flu needs an antiviral treatment. Healthy older kids and adults generally get better in a few days with rest, fluids, and over the counter medicine. Adding a medication that can cause nausea or vomiting, or increase risk of a drug-resistant flu strain developing isn’t always worth it.
But for some people, antivirals are important to prevent serious complications. The American Academy of Pediatrics (AAP) and the California Department of Public Health recommend antiviral treatment for:
Anyone hospitalized with flu
Anyone with severe and worsening illness
Kids under age 5 (especially under 2)
Adults age 65+
Pregnant women
Anyone who is immunocompromised
People with underlying conditions like asthma, diabetes, or heart disease
While Tamiflu (oseltamivir) has long been the default choice for flu treatment, Xofluza (baloxavir) is gaining popularity. Last week, CDPH issued an advisory to clinicians, reminding doctors about the importance of early antiviral treatment for people at risk for serious disease, and clarifying the criteria for considering Xofluza.
Guidelines for Flu Antiviral Treatment for Patients at Elevated Risk in California
While this graphic was created for clinicians, it’s helpful to see the guidance being given to the people who take care of you. Xofluza (baloxavir) is recommended for milder flu cases in people who are 5 years or older, not pregnant or breastfeeding, or immunocompromised. It’s one dose, and has similar effectiveness to Tamiflu. But it’s pricier, and insurance coverage is limited. Yesterday the team at YLE National posted a comprehensive overview of flu antivirals.
Flu vaccines. Antivirals are not a substitute for vaccines. Vaccination can reduce risk of severe illness, hospitalization, and death, even against the current dominant H3N2 subclade K strain. In England, where subclade K hit months ago, the vaccine was 70-75% effective at preventing hospitalization in children, and 30-40% effective for adults.
As of the end of 2025 (our latest available data) an estimated 46.4% of California adults age 18 and older had received this year’s shot, compared to 43.5% nationally. This time last year, 43.0% percent of California adults were vaccinated. We’re faring better compared to the nation and ourselves last year, but this feels like faint praise when less than half of California adults have gotten this year’s flu shot.
The vaccination picture for children is even more concerning: 41.9% of Californians age 17 and younger have gotten this season’s flu shot, slightly lower than the national rate (42.5%) and the rate in California this time last year (44.4%). With the first two pediatric flu deaths reported in California last week, low vaccination rates in kids is concerning. Last year we lost 44 children to flu in California, and nearly all weren’t vaccinated.
Covid
A winter surge is taking shape nationally. Covid wastewater levels for the U.S. are high, and rising, but our Western region is an exception. California levels are still low. There’s an unusually wide range of Covid activity across the U.S. right now, with regional levels spanning from “very low” to “very high.”
It’s hard to know when cases will pick up in California—there’s a complex interplay between seasonal conditions, human behavior, collective immunity, and viral evolution. Still, we’ve never had a winter without a Covid wave, so we should expect rates to increase soon. If you travel eastward in the U.S., odds are you’re going to an area where Covid is more active.
What this means for you
We’re in the thick of virus season. Masking up in crowded, indoor places can help prevent infection.
If you’re sick, stay home if you can, and wear a mask around others.
A flu test can help diagnose illness early enough to benefit from antiviral treatment. Contact your healthcare clinician for treatment options, following the latest guidance.
Importantly, it’s not too late to get vaccinated. Vaccines are available across California. You can visit MyTurn to schedule a shot today.
Updates
Mushroom poisonings. The outbreak of poisonings related to consuming death cap mushrooms (covered in my December 11 newsletter) is ongoing. Between November 18 and January 5, 35 cases of wild mushroom poisoning, including three deaths and three liver transplants, have been reported statewide. Most years, fewer than five total cases are reported. The most recent death was in a Sonoma County resident last week.
Case investigations found that some who ate poison mushrooms may have mistaken death caps for similar-appearing edible varieties found in their native countries. In response, the California Department of Public Health has developed messaging in English, Spanish, Chinese, Tagalog (Filipino), Vietnamese, and Mixteco (an indigenous Mexican language).
The surest way to avoid poisoning is to not consume mushrooms collected in the wild, at least during this period of elevated risk. Store bought supplies are safe. For those interested in learning more about safe mushroom hunting, trainings are available in English and Spanish over the coming weeks.
Spanish language translation of vaccine guidelines. Last week, we talked about changes to the childhood vaccination schedule. Here’s a NEW Spanish-language PDF of changes to vaccination schedule:
Vaccination Schedule Changes (Spanish)
68.3KB ∙ PDF file
That’s it for this week. Stay well, and we’ll see you again soon.
Love,
Matt
Dr. Matt Willis is the author of Your Local Epidemiologist in California. A California native, he’s served as a primary care physician, CDC epidemiologist, and public health officer for Marin County, where he guided the pandemic response. He lives in Marin with his wife, children, and their dogs Teddy and Ramona.
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