Latest Research: COVID-19 Vaccines
A selection of the latest COVID-19 vaccine research out of IDWeek 2022.
COVID-19 remained top of mind at IDWeek 2022, with dozens of posters, oral abstracts, and symposia presenting new research on the topic. Click through the slideshow to read a selection of the latest research on COVID-19 vaccines and follow along with Drug Topics® continuing coverage of IDWeek 2022.
COVID-19 Vaccination Associated With Lower Risk for ICU Admission, In-Hospital Mortality
Hospitalized patients who are fully vaccinated against COVID-19 have lower risks of both ICU admission and in-hospital mortality compared with those who are unvaccinated, according to one poster,1 with no differences noted based on the vaccine received (Moderna or Pfizer-BioNTech).
Laboratory-confirmed COVID-19 cases were retrospectively reviewed, inclusive of 3067 unvaccinated patients and 284 fully vaccinated patients (median age, 71 years). By study conclusion, 13.4% of patients required ICU admission and 15.5% of patients died. Multivariable-adjusted models indicated that those who were fully vaccinated had lower risks of both ICU admission and in-hospital mortality.
Vaccination Reduces Transmission Among Household Contacts
COVID-19 vaccination may be protective against SARS-CoV-2 transmission among household contacts, according to a group of Stanford University Researchers.2 Index cases of COVID-19 were prospectively enrolled in a study if they had tested positive for COVID-19 within the 10 days prior and did not have household contacts who had also tested positive, for a total of 163 participants (60 index cases and 103 household contacts).
In total, 20.2% of participants received at least 1 dose of a COVID-19 vaccine. Viral transmission occurred in 43.7% of households, with lower odds of SARS-CoV-2 transmission in household contacts who were vaccinated before study enrollment.
Although these data are useful in demonstrating that vaccination can help limit COVID-19 transmission, analyses were limited due to the low number of vaccinated participants, and study enrollment remains ongoing.
Three Doses of COVID-19 Vaccine Effective Against Severe Disease, Death With Omicron Variant
As long as 3 vaccine doses have been administered, COVID-19 vaccines are “extremely effective” in preventing severe disease and death in the context of the SARS-CoV-2 Omicron variant—but effectiveness “wanes substantially” in the course of 6 months.3
Data from January 2021 to April 2022 were used to estimate vaccine effectiveness. After 2 doses, effectiveness was >95% and >85% against Delta and Omicron SARS-CoV-2 variants in participants aged 15 to 59 and 60 to 79, waning by 5% to 10% and 15% to 20% in each group, respectively. In a group of adults aged 80 and older, effectiveness of 2 doses of the vaccine was “much lower” against Omicron—60% after vaccination and waning to 50% at 6 months. After 3 doses, vaccine effectiveness was >95% in all age groups except those aged 80 or older, where effectiveness was 90% against Omicron.
According to researchers, there was “little to no evidence” of variation in effectiveness between combinations of different vaccines.
Unvaccinated Individuals Represent Largest Proportion of Those Hospitalized With COVID-19
Patients who were not vaccinated against COVID-19 represented the largest proportion of individuals hospitalized in a retrospective cohort study that reviewed data from July through September 2021.4
In a group of 207 patients stratified by vaccination status (29% fully vaccinated), individuals who were unvaccinated were more likely to be younger (median age, 58 vs 71) and more likely to require advanced oxygen therapy, such as a high-flow nasal cannula, noninvasive ventilation, or mechanical ventilation, ICU admission, or 28-day all-cause mortality. Subgroup analyses showed that those who were unvaccinated were more likely to meet one of these outcomes if aged 65 years or older.
COVID-19 Vaccination During Pregnancy Not Associated With Increased Risks
Receiving a COVID-19 vaccine during pregnancy did not increase the risk of peripartum outcomes, but did decrease risks for NICU admission, intrauterine fetal death, and maternal COVID-19 infection, according to results of a systematic review and meta-analysis.5
A total of 9 observational studies inclusive of 81,349 vaccinated and 255,346 unvaccinated pregnant women were evaluated. Data indicated that COVID-19 vaccination during pregnancy was not associated with preterm or small for gestational age birth, or low Apgar score, nor was it associated with an increased risk of cesarean delivery, postpartum hemorrhage, or chorioamnionitis. COVID-19 vaccination, therefore, “should be encouraged for pregnant women.”
References
- Niu J, Sareli C, Mayer D, Visbal A, Sareli AE. A population-based propensity score-matched study of COVID-19 vaccination on clinical outcomes in hospitalized adult patients with COVID-19. Presented at: IDWeek 2022; October 19-23, 2022; Washington, D.C. Poster 1928.
- Burns JE, Altamirano J, Salinas J, et al. Effect of vaccination on household transmission of SARS-CoV-2. Presented at: Presented at: IDWeek 2022; October 19-23, 2022; Washington, D.C. Poster 1943.
- Lytras T, Mellou K, Gkolfinopoulou K, et al. Effectiveness of COVID-19 vaccines against severe disease and death and its durability over time against the Omicron variant. Presented at: IDWeek 2022; October 19-23, 2022; Washington, D.C. Poster 1944.
- Hoskins S, Restrepo MI, Cadena J. Effects of COVID-19 vaccines on outcomes among hospitalized COVID-19 patients. Presented at: IDWeek 2022; October 19-23, 2022; Washington, D.C. Poster 1945.
- Watanabe A, Yasuhara J, Iwagami M, et al. Peripartum outcomes associated with COVID-19 vaccination during pregnancy: A systematic review and meta-analysis. Presented at: IDWeek 2022; October 19-23, 2022; Washington, D.C. Poster 1963.