December 15, 2022

VIEW TRANSCRIPT

Clinical Reports

Progress Toward Poliomyelitis Eradication ― Afghanistan, January 2021–September 2022
- Afghanistan and Pakistan are the only countries where wild poliovirus type 1 (WPV1) remains endemic. Two WPV1 cases had been reported in 2022 as of September 30, compared with one case during the same period in 2021. No type 2 circulating vaccine-derived poliovirus was reported in 2022 compared with 43 cases in 2021. Since the political transition in August 2021, 3.5–4.5 million previously unreachable children were vaccinated; supplementary immunization activity (SIA) restrictions persist in the South Region. Ensuring implementation of high-quality SIAs in all parts of Afghanistan, especially in the high-risk provinces of the South Region, will accelerate progress toward interrupting WPV1 transmission.

Antiviral Therapeutics and Vaccines

Moderna Received FDA Emergency Use Authorization For Their Omicron-Targeting Bivalent Covid-19 Booster Vaccine In Children 6 Months Through 5 Years Of Age
- Moderna, Inc. (a biotechnology company pioneering messenger RNA (mRNA) therapeutics and vaccines, today announced it has received emergency use authorization (EUA) from the U.S. Food and Drug Administration (FDA) for its BA.4/BA.5 Omicron-targeting bivalent COVID-19 booster vaccine, mRNA-1273.222, in children 6 months through 5 years of age. The authorization is based on a 10 μg booster dose following a completed primary series of Moderna's original vaccine. The booster dose of mRNA-1273.222 contains mRNA encoding for the spike protein of BA.4/BA.5 as well as mRNA encoding for the original strain of the SARS-CoV-2 virus.
Reduced Risk for Mpox After Receipt of 1 or 2 Doses of JYNNEOS Vaccine Compared with Risk Among Unvaccinated Persons — 43 U.S. Jurisdictions, July 31–October 1, 2022
- Real-world data on the magnitude and durability of protection by JYNNEOS vaccine against monkeypox (mpox) remain limited. Among JYNNEOS vaccine-eligible men aged 18–49 years in 43 U.S. jurisdictions, mpox incidence among unvaccinated persons was 9.6 times as high as that among persons who had received 2 vaccine doses and 7.4 times as high as that among persons who had received only the first dose. Preliminary evidence indicates no difference in protection between subcutaneous and intradermal administration routes. Although further study is needed to determine the magnitude and durability of protection, evidence indicates that JYNNEOS vaccination provides protection against mpox. Vaccine-eligible persons should complete the 2-dose vaccination series.
Authorized Updated (Bivalent) COVID-19 Vaccines for Children Down to 6 Months of Age
- The U.S. Food and Drug Administration amended the emergency use authorizations (EUAs) of the updated (bivalent) Moderna and Pfizer-BioNTech COVID-19 vaccines to include use in children down to 6 months of age
Low neutralization of SARS-CoV-2 Omicron BA.2.75.2, BQ.1.1, and XBB.1 by parental mRNA vaccine or a BA.5-bivalent booster
- The newly emerged SARS-CoV-2 Omicron sublineages, including the BA.2-derived BA.2.75.2 and the BA.5-derived BQ.1.1 and XBB.1, have accumulated additional spike mutations that may affect vaccine effectiveness. Here researchers report neutralizing activities of three human serum panels collected from individuals 23–94 days after dose 4 of a parental mRNA vaccine, 14–32 days after a BA.5-bivalent-booster from individuals with 2–4 previous doses of parental mRNA vaccine, or 15–32 days after a BA.5-bivalent-booster from individuals with previous SARS-CoV-2 infection and 2–4 doses of parental mRNA vaccine. The results showed that a BA.5-bivalent-booster elicited a high neutralizing titer against BA.4/5 measured at 14- to 32-day post-boost; however, the BA.5-bivalent-booster did not produce robust neutralization against the newly emerged BA.2.75.2, BQ.1.1, or XBB.1. Previous infection significantly enhanced the magnitude and breadth of BA.5-bivalent-booster-elicited neutralization. This data supports a vaccine update strategy that future boosters should match newly emerged circulating SARS-CoV-2 variants.
Incidence of Viral Rebound After Treatment With Nirmatrelvir-Ritonavir and Molnupiravir
- In this cohort study of 12,629 adults in Hong Kong with COVID-19 who were hospitalized and had serial cycle threshold values measured, viral rebound (defined as a cycle threshold value >40 that decreased to ≤40) occurred in 68 antiviral nonusers (0.6%), 2 (1.0%) nirmatrelvir-ritonavir users, and 6 (0.8%) molnupiravir users. In this study, viral rebound was uncommon in adults with COVID-19 after treatment with nirmatrelvir-ritonavir and molnupiravir, suggesting that these novel oral antivirals should be prescribed to more patients with COVID-19 in the early phase of the infection.
The effectiveness of coronavirus disease 2019 (COVID-19) vaccine in the prevention of post–COVID-19 conditions: A systematic literature review and meta-analysis
- In total, 10 studies with 1,600,830 individuals evaluated the effect of vaccination on post–COVID-19 conditions, of which 6 studies were included in the meta-analysis. The pooled DOR for post–COVID-19 conditions among individuals vaccinated with at least 1 dose was 0.708 (95% confidence interval (CI), 0.692–0.725) with an estimated vaccine effectiveness of 29.2% (95% CI, 27.5%–30.8%). The vaccine effectiveness was 35.3% (95% CI, 32.3%–38.1%) among those who received the COVID-19 vaccine before having COVID-19, and 27.4% (95% CI, 25.4%–29.3%) among those who received it after having COVID-19. COVID-19 vaccination both before and after having COVID-19 significantly decreased post–COVID-19 conditions for the circulating variants during the study period although vaccine effectiveness was low.

Epidemiology

Reduced airborne transmission of SARS-CoV-2 BA.1 Omicron virus in Syrian hamsters
- The observation that the BA.1 variant of SARS-CoV-2 does not transmit efficiently via the air in Syrian hamsters appears to contrast with human epidemiological data. The reason for this difference in BA.1 transmission between humans and hamsters is not clear. One possible explanation is the sequence difference in angiotensin-converting enzyme 2 (ACE2) receptor, which could impact replication and transmission efficiency of BA.1 in hamsters. The reported attenuation of BA.1 in Syrian hamsters supports this observation. However, BA.1 was also attenuated in human ACE2-transgenic hamsters, implying that genetic differences in non-spike proteins, which can modulate innate and antiviral immunity, also contribute to the loss of airborne transmission of BA.1 in this model. It has also been reported that the Omicron variant is less dependent on the protease TMPRSS2 for spike protein cleavage and more dependent on cathepsins than the other variants, implying that the Omicron variant enters cells through a different route. This may have differential effects in humans and hamsters and reduce airborne transmission efficiency of Omicron variants between hamsters. Finally, it is possible that the changes in the spike protein of Omicron affect and reduce stability of the virus in the infected hosts. Differences in pH, salinity, or mucosal barrier between humans and hamsters before or after SARS-CoV-2 infection could contribute to differences in airborne transmission of the BA.1 Omicron variant between humans and hamsters. To summarize, the combined analysis from multiple groups using different isolates of the BA.1 Omicron variant demonstrate that BA.1 has reduced airborne transmission efficiency in Syrian hamsters compared to prior variants of SARS-CoV-2.