Abstract:

This episode of "This Week in Virology" features a clinical update with Dr. Daniel Griffin, covering a range of topics from COVID-19 to other infectious diseases. A key focus is on the benefits of vaccination. A study on maternal SARS-CoV-2 infection reveals an increased risk of neurodevelopmental issues in children exposed in utero, particularly during the third trimester. The discussion revisits the therapeutic potential of the HPV vaccine, highlighting a study showing it can help clear existing infections and prevent recurrence of cervical lesions, challenging the notion that it's only for prevention. Another segment addresses avian influenza, presenting evidence of asymptomatic H5N1 infections in humans, which suggests the true case fatality rate is lower than previously estimated. The episode also provides updates on rising measles cases in North America.

A significant portion is dedicated to a large-scale English study demonstrating that for children, the health risks associated with COVID-19 infection—including myocarditis, blood clots, and severe inflammatory conditions—are substantially higher than the risks from vaccination. Further evidence supports the use of Paxlovid, which reduces hospitalization risk by 74%, and shows that COVID-19 vaccination in adolescents reduces their risk of developing Long COVID by 36%.

A Clinical Update on Viral Diseases: Vaccination, Treatment, and Long-Term Outcomes

• 00:03:13 COVID-19 Infection During Pregnancy Increases Risk to Child: A retrospective study of over 18,000 births found that maternal SARS-CoV-2 infection is associated with an increased risk of adverse neurodevelopmental diagnoses in children by age three.

  • Key Takeaway: The risk is most pronounced with third-trimester exposure, where the incidence of neurodevelopmental issues rises from a baseline of ~10% to ~17%.

• 00:06:49 HPV Vaccine Shows Therapeutic Benefits: A systematic review demonstrates that the HPV vaccine is effective even in women who are already infected.

  • Detail: Vaccination after infection led to complete viral remission in up to 72.4% of women, compared to 45.7% in unvaccinated controls. It also lowered the risk of lesion recurrence after surgical procedures by 87%.
  • Key Takeaway: The evidence suggests it is "never too late" to get the HPV vaccine, as it can help the body clear existing infections and prevent progression to cancer.

• 00:15:08 Asymptomatic Avian Flu (H5N1) is Confirmed in Humans: A review of scientific literature confirms cases of asymptomatic H5N1 infection in humans, identified through molecular and serologic testing.

  • Key Takeaway: This finding challenges the previously estimated high case fatality rate (50-80%), which was based only on severe, symptomatic cases. The true infection fatality rate is likely much lower.

• 00:19:48 Measles Cases Continue to Rise: Updates show increasing case numbers in the US and Canada, putting both countries at risk of losing their measles elimination status.

  • Detail: An incident in Israel is highlighted where two fully vaccinated doctors contracted a mild form of measles from an unvaccinated child, demonstrating both the vaccine's ability to prevent severe disease and the ongoing risk posed by undervaccination.

• 00:24:03 COVID Infection Poses Far Greater Risk to Children Than Vaccination: A large population-based study in England compared health outcomes following COVID-19 infection versus vaccination in individuals under 18.

  • Detail: Infection was linked to a significantly higher risk of blood clots, low platelets, and a nearly 15-fold higher risk of inflammatory conditions. The risk of myocarditis was 3.5 times higher from the infection than from the vaccine.
  • Key Takeaway: The data provides strong evidence that vaccination is substantially safer for children than being unprotected and getting infected.

• 00:32:44 Paxlovid Remains Highly Effective at Preventing Hospitalization: A Canadian study confirmed that Paxlovid reduces the risk of COVID-19-associated hospitalization by 74%, regardless of vaccination status.

  • Key Takeaway: This reinforces the importance of using Paxlovid in at-risk individuals, despite listener reports of some doctors refusing to prescribe it based on misinformation.

• 00:40:13 Vaccination Reduces the Risk of Long COVID in Adolescents: A study in the US found that adolescents who were vaccinated prior to a SARS-CoV-2 infection had a 36% lower risk of developing Long COVID.

  • Detail: The incidence of Long COVID dropped from 20.7% in unvaccinated adolescents to 13.3% in those who were vaccinated.