RSV, COVID-19 and Flu Vaccines in Vials

August 24, 2023

Antiviral Therapeutics and Vaccines

  • FDA Approves First Vaccine for Pregnant Individuals to Prevent RSV in Infants
    The U.S. Food and Drug Administration approved Abrysvo (Respiratory Syncytial Virus Vaccine), the first vaccine approved for use in pregnant individuals to prevent lower respiratory tract disease (LRTD) and severe LRTD caused by respiratory syncytial virus (RSV) in infants from birth through 6 months of age. Abrysvo is approved for use at 32 through 36 weeks gestational age of pregnancy. Abrysvo is administered as a single dose injection into the muscle. The FDA approved Abrysvo in May for the prevention of LRTD caused by RSV in individuals 60 years of age and older.
  • Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2023–24 Influenza Season
    Routine annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications. All seasonal influenza vaccines expected to be available in the United States for the 2023–24 season are quadrivalent, containing hemagglutinin (HA) derived from one influenza A(H1N1)pdm09 virus, one influenza A(H3N2) virus, one influenza B/Victoria lineage virus, and one influenza B/Yamagata lineage virus. Inactivated influenza vaccines (IIV4s), recombinant influenza vaccine (RIV4), and live attenuated influenza vaccine (LAIV4) are expected to be available. For most persons who need only 1 dose of influenza vaccine for the season, vaccination should ideally be offered during September or October. However, vaccination should continue after October and throughout the season as long as influenza viruses are circulating and unexpired vaccine is available. Influenza vaccines might be available as early as July or August, but for most adults (particularly adults aged ≥65 years) and for pregnant persons in the first or second trimester, vaccination during July and August should be avoided unless there is concern that vaccination later in the season might not be possible. Certain children aged 6 months through 8 years need 2 doses; these children should receive the first dose as soon as possible after vaccine is available, including during July and August. Vaccination during July and August can be considered for children of any age who need only 1 dose for the season and for pregnant persons who are in the third trimester during these months if vaccine is available. ACIP recommends that all persons aged ≥6 months who do not have contraindications receive a licensed and age-appropriate seasonal influenza vaccine. With the exception of vaccination for adults aged ≥65 years, ACIP makes no preferential recommendation for a specific vaccine when more than one licensed, recommended, and age-appropriate vaccine is available. ACIP recommends that adults aged ≥65 years preferentially receive any one of the following higher dose or adjuvanted influenza vaccines: quadrivalent high-dose inactivated influenza vaccine (HD-IIV4), quadrivalent recombinant influenza vaccine (RIV4), or quadrivalent adjuvanted inactivated influenza vaccine (aIIV4). If none of these three vaccines is available at an opportunity for vaccine administration, then any other age-appropriate influenza vaccine should be used.
  • Nirmatrelvir resistance – de novo E166V/L50V mutations in an immunocompromised patient treated with prolonged nirmatrelvir/ritonavir monotherapy leading to clinical and virological treatment failure – a case report
    Resistance of SARS-CoV-2 to antivirals was shown to develop in immunocompromised individuals receiving remdesivir. Researchers describe an immunocompromised patient who was treated with repeated and prolonged courses of nirmatrelvir and developed de-novo E166V/L50F mutations in the Mpro region. These mutations were associates with clinical and virological treatment failure.


  • Progress Toward Poliomyelitis Eradication — Pakistan, January 2022–June 2023
    Transmission of wild poliovirus type 1 (WPV1) has never been interrupted in Pakistan, one of two countries with ongoing endemic transmission. Twenty WPV1 cases were reported in Pakistan during 2022, and one case during 2023 (as of June 2023), all clustered within a small geographic area in the southern region of Khyber Pakhtunkhwa province, an area with considerable security challenges and a history of vaccine hesitancy. Recent isolation of WPV1 from sewage in Karachi suggests surveillance gaps and improvements needed in immunization campaign quality. To interrupt WPV1 circulation, the Pakistan polio program needs to meticulously track and sustain innovative efforts to vaccinate children who are regularly missed during polio vaccination activities, especially in reservoir areas affected by conflict and insecurity.
  • Modeling poliovirus transmission and responses in New York State
    In July 2022, New York State (NYS) reported a case of paralytic polio in an unvaccinated young adult, and subsequent wastewater surveillance confirmed sustained local transmission of type 2 vaccine-derived poliovirus (VDPV2) in NYS with genetic linkage to the paralyzed patient. Researchers adapted an established poliovirus transmission and oral poliovirus vaccine (OPV) evolution model to characterize dynamics of poliovirus transmission in NYS, including consideration of the immunization activities performed as part of the declared state of emergency. Despite sustained transmission of imported VDPV2 in NYS involving potentially thousands of individuals (depending on seasonality, population structure and mixing assumptions) in 2022, the expected number of additional paralytic cases in years 2023 and beyond is small (less than 0.5). However, continued transmission and/or reintroduction of poliovirus into NYS and other populations remains a possible risk in communities that do not achieve and maintain high immunization coverage. In countries such as the US that use only inactivated poliovirus vaccine, even with high average immunization coverage, imported polioviruses may circulate and pose a small but non-zero risk of causing paralysis in non-immune individuals.
  • Incidence of New-Onset Hypertension Post–COVID-19: Comparison With Influenza
    SARS-CoV-2 may trigger new-onset persistent hypertension. This study investigated the incidence and risk factors associated with new-onset persistent hypertension during COVID-19 hospitalization and at ≈6-month follow-up compared with influenza. This retrospective observational study was conducted in a major academic health system in New York City. Participants included 45 398 patients with COVID-19 (March 2020 to August 2022) and 13 864 influenza patients (January 2018 to August 2022) without a history of hypertension. At 6-month follow-up, new-onset persistent hypertension was seen in 20.6% of hospitalized patients with COVID-19 and 10.85% of nonhospitalized patients with COVID-19. Persistent hypertension incidence among hospitalized patients did not vary across the pandemic, whereas that of among hospitalized patients decreased from 20% in March 2020 to ≈10% in October 2020 (R
    2=0.79, P=0.003) and then plateaued thereafter. Hospitalized patients with COVID-19 were 2.23 ([95% CI, 1.48–3.54]; P<0.001) times and nonhospitalized patients with COVID-19 were 1.52 ([95% CI, 1.22–1.90]; P<0.01) times more likely to develop persistent hypertension than influenza counterparts. Persistent hypertension was more common among older adults, males, patients with preexisting comorbidities (chronic obstructive pulmonary disease, coronary artery disease, chronic kidney disease), and those who were treated with pressor and corticosteroid medications. Mathematical models predicted persistent hypertension with 79% to 86% accuracy. In addition, 21.0% of hospitalized patients with COVID-19 with no prior hypertension developed hypertension during COVID-19 hospitalization. Incidence of new-onset persistent hypertension in patients with COVID-19 is higher than those with influenza, likely constituting a major health burden given the sheer number of patients with COVID-19. Screening at-risk patients for hypertension following COVID-19 illness may be warranted.
  • Postacute sequelae of COVID-19 at 2 years
    Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can lead to postacute sequelae in multiple organ systems, but evidence is mostly limited to the first year postinfection. Researchers built a cohort of 138,818 individuals with SARS-CoV-2 infection and 5,985,227 noninfected control group from the US Department of Veterans Affairs and followed them for 2 years to estimate the risks of death and 80 prespecified postacute sequelae of COVID-19 (PASC) according to care setting during the acute phase of infection. The increased risk of death was not significant beyond 6 months after infection among nonhospitalized but remained significantly elevated through the 2 years in hospitalized individuals. Within the 80 prespecified sequelae, 69% and 35% of them became not significant at 2 years after infection among nonhospitalized and hospitalized individuals, respectively. Cumulatively at 2 years, PASC contributed 80.4 (95% confidence interval (CI): 71.6–89.6) and 642.8 (95% CI: 596.9–689.3) disability-adjusted life years (DALYs) per 1,000 persons among nonhospitalized and hospitalized individuals; 25.3% (18.9–31.0%) and 21.3% (18.2–24.5%) of the cumulative 2-year DALYs in nonhospitalized and hospitalized were from the second year. In sum, while risks of many sequelae declined 2 years after infection, the substantial cumulative burden of health loss due to PASC calls for attention to the care needs of people with long-term health effects due to SARS-CoV-2 infection.

Situation Dashboards


World Health Organization (WHO)

Novel Coronavirus (COVID-19) Situation from World Health Organization (WHO)

Johns Hopkins University (JHU)

Coronavirus COVID-19 Global Cases by the Center for Systems Science and Engineering (CSSE) at JHU

COVID-19 in US and Canada

1Point3Acres Real-Time Coronavirus (COVID-19) Updates in US and Canada with Credible Sources

Genomic Epidemiology COVID-19

Genomic Epidemiology of (COVID-19) Maintained by the Nextstrain team, enabled by data from GISAID.

Sources for COVID-19 Information


World Health Organization (WHO)


Centers for Disease Control, US


International Society for Infectious Diseases


This Week in Virology (TWIV)

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