> one of the only things that actually worked to stop people dying was the roll out of effective vaccines

"A total of 913 participants were included in the final analysis. The adjusted ORs for COVID-19 infection among vaccinated individuals compared to unvaccinated individuals were 1.85 (95% CI: 1.33-2.57, p < 0.001). The odds of contracting COVID-19 increased with the number of vaccine doses: one to two doses (OR: 1.63, 95% CI: 1.08-2.46, p = 0.020), three to four doses (OR: 2.04, 95% CI: 1.35-3.08, p = 0.001), and five to seven doses (OR: 2.21, 95% CI: 1.07-4.56, p = 0.033)." - ["Behavioral and Health Outcomes of mRNA COVID-19 Vaccination: A Case-Control Study in Japanese Small and Medium-Sized Enterprises" (2024)](https://www.cureus.com/articles/313843-behavioral-and-health...)

"the bivalent-vaccinated group had a slightly but statistically significantly higher infection rate than the unvaccinated group in the statewide category and the age ≥50 years category" - ["COVID-19 Infection Rates in Vaccinated and Unvaccinated Inmates: A Retrospective Cohort Study" (2023)](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10482361/)

"The risk of COVID-19 also varied by the number of COVID-19 vaccine doses previously received. The higher the number of vaccines previously received, the higher the risk of contracting COVID-19" - ["Effectiveness of the Coronavirus Disease 2019 (COVID-19) Bivalent Vaccine" (2022)](https://www.medrxiv.org/content/10.1101/2022.12.17.22283625v...)

"Confirmed infection rates increased according to time elapsed since the last immunity-conferring event in all cohorts. For unvaccinated previously infected individuals they increased from 10.5 per 100,000 risk-days for those previously infected 4-6 months ago to 30.2 for those previously infected over a year ago. For individuals receiving a single dose following prior infection they increased from 3.7 per 100,000 person days among those vaccinated in the past two months to 11.6 for those vaccinated over 6 months ago. For vaccinated previously uninfected individuals the rate per 100,000 person days increased from 21.1 for persons vaccinated within the first two months to 88.9 for those vaccinated more than 6 months ago." - ["Protection and waning of natural and hybrid COVID-19 immunity" (2021)](https://www.medrxiv.org/content/10.1101/2021.12.04.21267114v...)