This episode of "This Week in Virology" provides a clinical update from Dr. Daniel Griffin, framed by the disruption of a US government shutdown, which has halted public health data reporting and led to the chaotic firing and rehiring of CDC officials. The discussion covers H5N1 influenza, detailing a study on its stability in raw milk cheese, which found the virus remains infectious unless the cheese is acidified to a pH of 5. Dr. Griffin addresses the worsening measles epidemic, with hundreds of students in quarantine and the US on the verge of losing its elimination status. Influenza updates include an early season in Japan and a meta-analysis demonstrating the flu vaccine's effectiveness against severe outcomes like hospitalization (42%) and death (36%), with significantly higher efficacy in children. For COVID-19, the hosts review a study showing a slight, non-durable advantage for the Novavax vaccine over Pfizer's in adolescents and discuss results from the PLATCOV trial that confirmed the efficacy of antivirals nirmatrelvir and ensitrelvir, while ivermectin performed worse than no treatment. The episode concludes with an analysis of Long COVID patient trajectories and a listener Q&A covering the unavailability of separate MMR vaccines, post-viral type 1 diabetes, and rare genetic predispositions to severe measles vaccine reactions.
Clinical Updates on H5N1, Measles, Flu, and COVID-19 Amidst Government Shutdown
3:47 Government Shutdown and CDC Firings: Dr. Griffin expresses dismay over the US government shutdown and reports that dozens of CDC officials, including disease detectives and staff from the Morbidity and Mortality Weekly Report (MMWR), were mistakenly fired due to a "coding error" before the notices were rescinded. This highlights the instability and political disruption affecting public health infrastructure.
5:44 H5N1 Stability in Raw Milk Cheese: A Nature Medicine study found that the H5N1 influenza virus can remain infectious in raw milk cheeses for up to 120 days when the pH is 6.6 or 5.8. However, acidifying the cheese to a pH of 5 prevented the virus from surviving the cheese-making process. Ferrets fed contaminated raw milk became infected, but those fed the cheese did not, suggesting a potential but not fully realized transmission risk.
13:00 Measles Outbreak and Quarantine: Hundreds of unvaccinated students in states like South Carolina and Minnesota are being quarantined due to ongoing measles outbreaks. The US is on the verge of losing its measles elimination status. Dr. Griffin references the Johns Hopkins measles tracker as a source of data, as official government reporting has been halted.
15:33 Early Influenza Season and Vaccine Effectiveness: Japan is experiencing an early and severe flu season, with school closures occurring about five weeks ahead of schedule. A meta-analysis published in CMI found that flu vaccination provides significant protection against severe outcomes: 42% against hospitalization, 36% against death, 51% against pneumonia, and 55% against requiring ventilatory support. Key Takeaway: Vaccine effectiveness was up to two-fold higher in children compared to adults.
23:10 Novavax vs. Pfizer COVID-19 Vaccine: A study in South Korean adolescents compared the Novavax and Pfizer COVID-19 vaccines. The results showed Novavax had a slight, statistically significant advantage in effectiveness in the first 100 days after a primary series, but this advantage diminished over time.
29:24 Antiviral Trial Results for COVID-19: The PLATCOV trial compared different oral antivirals for early COVID-19. Both ensitrelvir and nirmatrelvir (the active component of Paxlovid) were effective at accelerating viral clearance compared to no treatment. Key Finding: An arm of the trial studying high-dose ivermectin found that patients receiving it had slower viral clearance than those who received no drug at all.
33:26 Long COVID Patient Trajectories: An exploratory analysis of the STOP-PASC clinical trial (which previously found no benefit for Paxlovid in Long COVID) used modeling to identify different patient outcome trajectories. They could distinguish subgroups of patients who were improving, worsening, or had persistent symptoms, but this did not identify any subgroup that benefited from Paxlovid treatment.
37:11 Listener Q&A - Separating MMR Vaccine: A listener points out that a political recommendation to "split up" the MMR vaccine is impossible, as separate measles, mumps, and rubella vaccines are no longer manufactured or available in the US.
40:05 Listener Q&A - Post-Viral Type 1 Diabetes: Dr. Griffin confirms that there is an observed increase in type 1 diabetes in teens following viral infections like influenza, a phenomenon also seen post-COVID.
43:05 Listener Q&A - Rare Measles Vaccine Reaction: A listener clarifies a previous question by referencing a case report of a child with a homozygous mutation in the IFNAR2 gene who suffered a severe adverse reaction to the live measles vaccine, highlighting a rare but documented risk for individuals with specific interferon-related genetic disorders.