RESUMEN
To date, the effectiveness of COVID-19 vaccines and booster doses has yet to be evaluated in longitudinal head-to-head studies. This single-center longitudinal study assessed the effectiveness of ChAdOx1 nCoV-19, BNT162b2, and mRNA-1273 vaccines and assessed two BNT162b2 boosters in 1550 participants, of whom 26% had comorbidities. In addition, the SARS-CoV-2 antibody dynamics was monitored. A group of 1500 unvaccinated subjects was included as the controls. The study's endpoint was the development of virologically-proven COVID-19 cases after vaccine completion, while the secondary endpoint was hospitalizations due to severe COVID-19. Overall, 23 (4.6%), 16 (3%), and 18 (3.8%) participants vaccinated with ChAdOx1 nCoV-19, BNT162b2, and mRNA-1273, respectively, developed COVID-19 after vaccine completion, with an effectiveness of 89%, 92%, and 90%. Ten COVID-19 cases were reported in participants with comorbidities, three of whom were hospitalized. No hospitalizations occurred after boosters. SARS-CoV-2 antibody levels peaked 2-4 weeks after the second vaccine dose but declined after a mean of 28.50 ± 3.48 weeks. Booster doses significantly enhanced antibody responses. Antibody titers ≤ 154 U/mL were associated with a higher risk of COVID-19 emergence. Thus, COVID-19 vaccines effectively reduced COVID-19 and prevented severe disease. The vaccine-induced SARS-CoV-2 antibody responses declined after 28-32 weeks. Booster doses induced significant maintained responses. SARS-CoV-2 antibody levels may help determine the timing and need for vaccine booster doses.
Asunto(s)
COVID-19 , Vacunas , Humanos , Vacuna nCoV-2019 mRNA-1273 , Vacuna BNT162 , Vacunas contra la COVID-19 , ChAdOx1 nCoV-19 , Arena , Estudios Longitudinales , Estudios Prospectivos , COVID-19/prevención & control , SARS-CoV-2/genética , Vacunas de ARNm , Anticuerpos AntiviralesRESUMEN
Background: The Al-Kharj colorectal cancer (CRC) screening program was implemented for five years (2017-2022) in a central urban area of Riyadh Province, Saudi Arabia, to assess the participation and impact of the program in average-risk individuals. Methods: The high sensitivity-guaiac based-fecal occult blood test (HSgFOBT) was used as a first-line investigation to identify asymptomatic patients, aged 45-75 years, requiring CRC screening using colonoscopy. The program was run in three tertiary hospitals in the area. Results: The five-year participation rate was 73% (35,640/48,897). The average age was 53 years (range 45-75), 49% were female (17,464/35,640), all were asymptomatic, and 77% had adequate bowel preparation. The HSgFOBT (+) rate was 6.3% (n = 2245), and 76% (n = 1701) of these underwent colonoscopy. The prevalence of findings were as follows: CRC, 4.8% (81/1701); advanced adenoma, 9.5% (162/1701); adenoma, 15.9% (270/1701); non-adenomatous polyps, 7.9% (135/1701); and no polyps or tumors, 25.4% (432/1701). Among participants aged 45-50 years, early onset-CRC had female predominance, while those ≥50 years with late onset-CRC were predominantly male. CRC was more prevalent in the left colon (P < 0.005). Conclusions: Approximately one-third of the participants diagnosed with CRC had early-onset CRC. Screening participation was desirable for the defined target population. Public education is necessary along with expanded colonoscopy resources to continue further citizen participation.