Roughly 5,400 measles cases and 10 deaths. A curve that is "just rising," with no plateau in sight. And a formal process already underway to strip the United States of a status it has held for 26 years.
That is the assessment Daniel Griffin, an infectious disease physician who delivers the weekly clinical update on This Week in Virology, laid out in the episode recorded November 13. He expects the Pan American Health Organization to formally revoke US measles elimination status at a meeting of eight public health officials advising a UN arm, and he does not think the outcome is in doubt. Neither does host Vincent Racaniello.
"It's going to — we're going to lose it, okay? Forget it," Griffin said, regardless of what PAHO decides.
The number that matters is not the designation but the trajectory. US cases rose about 350 in a single week. When Racaniello pulled up the Johns Hopkins measles tracker during the recording, he described the American curve as resembling the Democratic Republic of Congo's Ebola curve — climbing, not bending.
Canada already ran this experiment, and it took 49 weeks
If you want to know how a wealthy country loses elimination status, Canada is the case study, and Griffin walks through it in detail.
Canada achieved elimination in 1998 after adding a second MMR dose and a school-age catch-up program. Ontario went from more than 5,000 cases in 1991 to 101 cases across the decade from 2013 to 2023.
Then, in October 2024, a measles exposure at a wedding in New Brunswick started a chain that ran for 49 weeks.
Canada outbreak metric (Oct 2024–Oct 2025)ValueTotal cases2,377 over 49 weeksCases aged 19 or younger~75%Unvaccinated~90%Unknown vaccination status~4%Hospitalized7%Infections during pregnancy2%Congenital measles infections10Encephalitis cases1Deaths1 infant
PAHO determined in November 2025 that Canada had lost elimination status.
The detail Griffin lingers on is why the Canadian outbreak stayed contained. It burned largely within under-vaccinated communities because the surrounding areas had coverage above 95%. That firewall is the whole ballgame. In the US, Griffin argues, the firewall is thinner — and the health secretary's messaging is actively widening the gap.
Racaniello adds the blunt statistic: 97% of US measles cases are in unvaccinated people.
The doctors' schedule and the secretary's message are now two different products
Here is the part that would have been unremarkable in 2019 and is remarkable now. Four national medical societies — the American Academy of Allergy, Asthma and Immunology, the American Thoracic Society, the American College of Chest Physicians, and the Society of Critical Care Medicine — endorsed flu, RSV and COVID-19 recommendations aligned with the American Academy of Pediatrics, the American Academy of Family Physicians, the American College of Obstetricians and Gynecologists and the Infectious Disease Society of America.
That is eight professional bodies on one page. Griffin walks through the schedule in granular detail and tells listeners plainly to disregard the federal counter-messaging from HHS Secretary Robert F. Kennedy Jr.
Racaniello is even more direct. "This is great. This is very clear, simple," he said of the consensus guidance. "And folks, it does contradict what RFK Jr. says, but ignore him cuz he doesn't know what he's talking about."
VaccineWhoSchedule and notesInfluenzaEveryone 6 months and olderAnnual; 65+ should get high-dose, adjuvanted or recombinant, but take standard if unavailable; egg allergy is not a contraindicationRSV (adults)All adults 75+; adults 50–75 at higher riskOne-time; Arexvy (GSK) and mRESVIA (Moderna) approved for 60+ or 18–59 at increased risk; Abrysvo (Pfizer) is the option for pregnancy at 32–36 weeksRSV (infants)Babies under 8 months whose mothers were not vaccinated in pregnancyPassive antibody (nirsevimab/Beyfortus or clesrovimab); a second, higher weight-based dose allowed for children up to 24 months still vulnerable in a second seasonCOVID-19All adults 18+Annual, plus a second dose for adults 65+ about six months later; recommended in pregnancy; children 6–23 months and older at-risk children and teens
The RSV row is where the commercial map lives. GSK's Arexvy and Moderna's mRESVIA cover older adults and at-risk adults 18 to 59. Neither carries a pregnancy label. That leaves Pfizer's Abrysvo as the sole option for maternal immunization at 32 to 36 weeks — a differentiated position in a market where the three products otherwise compete for the same pharmacy shelf.
The COVID-19 second dose for people 65 and older is framed around antibody waning at roughly six months, with T-cell responses proving more durable. Griffin suggests an October dose and an April follow-up for the Northern Hemisphere.
Flu arrived early and has already killed three children
The CDC flu map is no longer uniformly green. Louisiana and South Carolina are showing high activity, with moderate activity appearing in Texas, Florida and the West Coast.
Three pediatric flu deaths have already been recorded this season. Last season, the toll exceeded 200 children — and Griffin's point is the one that undoes the usual reassurance.
"Half of those over 200 kids were completely healthy until they got the flu and died," he said.
Treatment and post-exposure prophylaxis exist, and the message is to contact a provider early rather than wait. Racaniello notes the calendar problem: most adults should have been vaccinated in September or October, and it is now mid-November.
Dengue is now spreading in Florida, and the first infection can kill
A New York Times profile of a Florida woman named Gay Small, who died after a mosquito bite during her daily walks, anchors this section. She is the only fatality so far among hundreds sickened in a Florida outbreak that scientists and officials are still struggling to explain. Griffin cites University of Florida biostatistician Ira Longini saying US dengue outbreaks will worsen in the coming years. Most current Florida transmission is local, not travel-associated.
Griffin then dismantles a piece of conventional wisdom. Severe dengue is classically taught as a second-infection phenomenon through antibody-dependent enhancement. But he says a substantial share of severe cases and deaths worldwide — particularly in young children and in Southeast Asia — occur on a first infection, and roughly a quarter of travelers sick enough to be hospitalized are experiencing their first dengue.
No dengue vaccine is licensed in the US. Griffin says that will need revisiting if dengue becomes endemic. He also flags chikungunya and screwworm as emerging Florida-region concerns.
Ebola in the DRC is the fastest-growing outbreak on record, and the vaccine is still unproven
The DRC Ebola outbreak that began in May 2026 has passed 11,000 cases and more than 5,000 confirmed deaths — the second largest in history and the fastest growing on record.
Médecins Sans Frontières is pressing the WHO to lift restrictions that limit the rVSV vaccine to research use. Griffin resists, and Racaniello agrees with him: anecdotal cross-protection is not evidence, and this will not be the last Bundibugyo outbreak. Griffin wants to know whether the vaccine works before expanding use.
The operational picture is worse than the regulatory one. DRC contact tracing is already resource-constrained, and US restrictions on responders — including a 21-day work restriction on return — hamper the response. A separate Bundibugyo-specific vaccine is about to come online and will be tested.
An intratumoral flu shot shrank melanoma tumors
This is the item most likely to travel beyond infectious disease circles. A phase 1b trial published in the Journal for Immunotherapy of Cancer injected quadrivalent unadjuvanted seasonal flu vaccine (Flu Cellvax) directly into melanoma tumors, after a standard intramuscular flu shot, in 18 patients with a dose-escalation design. The rationale came from mouse melanoma models in which intratumoral flu vaccine reduced tumor growth and sensitized resistant tumors to immune checkpoint blockade.
Phase 1b outcomeResultTumor-infiltrating lymphocytes79% of samplesTumor regression~40%Complete pathologic responses3 (one with germinal center formation)Th1 to Treg ratio1.5-fold increaseMyeloid-derived suppressor cells70% reductionExhausted CD4 T cells65% reductionCytokine shiftsUp: IL-15, GM-CSF, CXCL10, CCL3, TNF-alpha; down: IL-1 beta, IL-13
Both Griffin and Racaniello flag the practical ceiling. Not every tumor is needle-accessible, melanoma patients often have many lesions, and systemic delivery would be preferable. Griffin notes the complete responses were confirmed pathologically after surgical resection, and that phase 2 and phase 3 work remains. He connects the finding to earlier observations that COVID-19 vaccination improved immunotherapy responses in cancer patients — the same idea that a generic immune jolt can unmask a tumor.
Polio and H5N1 keep showing the same pattern
Syria's Ministry of Health, with WHO and UNICEF support, launched a response after circulating vaccine-derived poliovirus type 1 was detected in two children — aged 16 months and 13 months — who developed paralysis in Deir ez-Zor.
Racaniello restates the case for moving from the attenuated Sabin oral vaccine to injectable IPV, arguing that cost and cold-chain objections are surmountable. He concedes the awkward corollary: unimmunized children remain at risk from circulating virus even after a country switches vaccines.
On H5N1, Griffin highlights a JP Whalen post on X showing a conceptual diagram of mink respiratory tracts carrying both alpha-2,3 and alpha-2,6 linked sialic acid receptors — the avian and human receptor types — with the caveat that receptor preference is only one factor in transmission. He and Racaniello note pigs share this dual-receptor trait. Both call for ending mink farming for fur.
Griffin also reports screwworm detections at six fly-trap sites, 41 cases in November as of the 12th, and spread into Arizona and Texas. He calls for restoring the irradiated-male release and surveillance program with Mexico and Central America.
The view from inside the Bundibugyo evacuation
A listener letter gives the episode its most human passage. Wes, an advisor in Tropical Medicine and Infectious Diseases at the State Department's Bureau of Medical Services, describes the behind-the-scenes account of the Bundibugyo evacuations Griffin and Racaniello covered in late August 2026.
Wes recounts hours of investigator training for US and German care teams, overnight shipments, diplomatic action to permit importation, colleagues hand-delivering remdesivir before takeoff, and an in-flight infusion given with consent. The team offered post-exposure prophylaxis to family members with high-risk contact, the interventions are now being studied in the DRC's PARTNERS adaptive trial, and the US government has made monoclonal antibody available to that trial while supplying compassionate-use courses to the DRC Ministry of Health.
Griffin's verdict: "a fantastic story."
Three listener questions, and where the evidence actually stops
A listener asks whether Paxlovid helped her husband, who tested positive again on day nine after a negative result. Griffin's answer is that repeat testing after a positive is pointless — the relevant outcome is symptom severity, not test positivity. He cites more than 200 Paxlovid studies and a roughly 50% reduction in second-week hospitalization, and notes he still has patients on oxygen with COVID-19.
Another listener asks about a UK estimate of 47.6% autumn 2025 vaccine effectiveness against hospitalization at five to nine weeks post-vaccination. Griffin calls that "pretty solid" and says the money was well spent.
A third asks about spacing the pneumonia, shingles and COVID-19 vaccines at age 50. The COVID-19 shot is the time-critical one, the others can be given simultaneously, and the second shingles dose follows in one to three months.
Then comes the question that reveals the gap between trial data and patient expectation. A parent asks about a healthy 10-year-old who had a strong reaction to prior shots, given that antibody protection lasts about six months while T-cell responses last longer. Racaniello points out the guidance does not actually cover that child: the societies recommend COVID-19 vaccination for children 6 to 23 months and for older at-risk children. No trial was designed to answer the frequency question for a healthy preteen. The parent is left to weigh it alone.
What to watch
Three threads carry the next few months. Whether PAHO formally revokes US measles elimination status — and whether the curve bends before it does. Whether the rVSV Ebola vaccine demonstrates efficacy in the DRC trial before pressure for compassionate use becomes irresistible. And whether the intratumoral flu vaccine concept survives phase 2, given that its delivery constraints may confine it to accessible lesions.
The larger story is structural. Diseases that were controlled a generation ago are moving back into wealthy countries, and the professional consensus on how to respond is now openly at odds with federal public health leadership in the United States. For anyone modeling vaccine demand, the RSV label segmentation and the unified-society schedule are the operative facts — the pharmacy counter will follow the doctors' guidance and the insurers' formularies, while federal messaging runs on a separate track. The risk premium sits in exactly that divergence: policy volatility, uneven coverage, and outbreaks that start in under-vaccinated pockets and do not stay there. The DRC's 11,000 Ebola cases and Florida's first dengue death are not abstractions for a portfolio. They are the same failure mode, priced differently.
