Assessment of COVID-19 vaccine effectiveness in a nation with a low vaccination coverage: insights from real-world data and propensity score matched analyses

References

• Vardell E. Global health observatory data repository. Med Ref Serv Q. 2020;39(1):1–9.
   PubMedGoogle Scholar
• Pancheva R, Chamova R, Rohova M, et al. Bulgarian general population attitude to mandatory COVID-19 vaccination: a nationwide cross-sectional study. Clin Epidemiol Global Health. 2023;23:101391. doi: 10.1016/j.cegh.2023.101391.
   Web of Science ®Google Scholar
• Heyerdahl LW, Vray M, Lana B, et al. Conditionality of COVID-19 vaccine acceptance in European countries. Vaccine. 2022;40(9):1191–1197. doi: 10.1016/j.vaccine.2022.01.054.
   PubMed Web of Science ®Google Scholar
• Life expectancy by age and sex EUROSTAT2023. [updated 26.09.202316.10.2023]. Available from: https://ec.europa.eu/eurostat/databrowser/view/DEMO_MLEXPEC/bookmark/table?lang=en&bookmarkId=34d45433-5f98-419b-90e5-063518da130b.
   Google Scholar
• Steinert JI, Sternberg H, Prince H, et al. COVID-19 vaccine hesitancy in eight european countries: prevalence, determinants, and heterogeneity. Sci Adv. 2022;8(17):eabm9825.
   PubMed Web of Science ®Google Scholar
• Tsanova D, Georgieva S, Kamburova M, et al. Regional health and social inequalities in Bulgaria. Eur J Public Health. 2023;33(Supplement_2):ckad160.225. doi: 10.1093/eurpub/ckad160.225.
   Google Scholar
• Rangachev A, Marinov GK, Mladenov M. The demographic and geographic impact of the COVID pandemic in Bulgaria and Eastern Europe in 2020. Sci Rep. 2022;12(1):6333. doi: 10.1038/s41598-022-09790-w.
   PubMed Web of Science ®Google Scholar
• Polack FP, Thomas SJ, Kitchin N, et al. Safety and efficacy of the BNT162b2 mRNA covid-19 vaccine. N Engl J Med. 2020;383(27):2603–2615. doi: 10.1056/NEJMoa2034577.
   PubMed Web of Science ®Google Scholar
• Baden LR, El Sahly HM, Essink B, et al. Efficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine. N Engl J Med. 2020;384(5):403–416. doi: 10.1056/NEJMoa2035389.
   PubMed Web of Science ®Google Scholar
• Lau JJ, Cheng SMS, Leung K, et al. Real-world COVID-19 vaccine effectiveness against the omicron BA.2 variant in a SARS-CoV-2 infection-naive population. Nat Med. 2023;29(2):348–357. doi: 10.1038/s41591-023-02219-5.
   PubMed Web of Science ®Google Scholar
• van de Schoot T, Pavlova M, Atanasova E, et al. Preferences of Bulgarian consumers for quality, access and price attributes of healthcare services-result of a discrete choice experiment. Int J Health Plann Manage. 2017;32(1):e47–e71.
   PubMed Web of Science ®Google Scholar
• Unified information portal for COVID-19: Ministry of Health of the Republic of Bulgaria. 2024. Available from: https://coronavirus.bg/.
   Google Scholar
• Kim L, Garg S, O’Halloran A, et al. Risk factors for intensive care unit admission and In-hospital mortality among hospitalized adults identified through the US coronavirus disease 2019 (COVID-19)-associated hospitalization surveillance network (COVID-NET). Clin Infect Dis. 2020;72(9):e206–e14. doi: 10.1093/cid/ciaa1012.
   Web of Science ®Google Scholar
• Dimitrov G, Kalinov K, Valkov T. COVID-19 vaccination outcomes in patients with a solid malignancy: insights from extensive real-world data and propensity score matched analyses. Am J Infect Control. 2024;52(6):678–682.
   PubMedGoogle Scholar
• Dimitrov G, Valkov T, Batselova H, et al. Nationwide analysis of the impact of COVID-19 in patients with a cardiovascular, oncological or chronic pulmonary disease in the context of an Eastern European country with a low vaccination rate, Bulgaria: March 2020–April 2022. BMJ Open. 2023;13(8):e068431. PubMed PMID37532478. Pubmed Central PMCID: 10401219. doi: 10.1136/bmjopen-2022-068431.
   PubMed Web of Science ®Google Scholar
• Yek C, Warner S, Wiltz JL, et al. Risk factors for severe COVID-19 outcomes among persons aged ≥18 years who completed a primary COVID-19 vaccination series - 465 health care facilities, United States, december 2020-October 2021. MMWR Morb Mortal Wkly Rep. 2022;71(1):19–25.
   PubMed Web of Science ®Google Scholar
• Ranzani OT, Hitchings MDT, Dorion M, et al. Effectiveness of the CoronaVac vaccine in older adults during a gamma variant associated epidemic of covid-19 in Brazil: test negative case-control study. BMJ. 2021;374:n2015. PubMed PMIDdoi: 10.1136/bmj.n2015.
   PubMed Web of Science ®Google Scholar
• Menni C, May A, Polidori L, et al. COVID-19 vaccine waning and effectiveness and side-effects of boosters: a prospective community study from the ZOE COVID study. Lancet Infect Dis. 2022;22(7):1002–1010.
   PubMed Web of Science ®Google Scholar
• Levin AT, Owusu-Boaitey N, Pugh S, et al. Assessing the burden of COVID-19 in developing countries: systematic review, meta-analysis and public policy implications. BMJ Glob Health. 2022;7(5):e008477. PubMed PMID35618305Pubmed Central PMCID:doi: 10.1136/bmjgh-2022-008477.
   PubMed Web of Science ®Google Scholar
• European C, Larson H, Figueiredo A, Directorate-General for H, Food S, et al. State of vaccine confidence in the EU 2018: Publications Office; 2018.
   Google Scholar
• Gallup-international. The lack of sufficient reliable information about the vaccines against COVID-19, reinfection of the virus and the presence of chronic diseases are among the most frequently cited reasons for refusing vaccination against COVID-19 at the moment gallup-international.bg2022 [06.07.2022]. 2022. Available from: gallup-international.bg/45706/new-covid-vaccination-survey-reasons-for-refusing-vaccination/.
   Google Scholar
• Matveeva O, Shabalina SA. Comparison of vaccination and booster rates and their impact on excess mortality during the COVID-19 pandemic in European countries. Front Immunol. 2023;14:1151311–37483606. PubMed PMIDPubmed Central PMCID: 10357837. doi: 10.3389/fimmu.2023.1151311.
   PubMed Web of Science ®Google Scholar
• Hammond J, Leister-Tebbe H, Gardner A, et al. Oral nirmatrelvir for high-risk, nonhospitalized adults with covid-19. N Engl J Med. 2022;386(15):1397–1408. doi: 10.1056/NEJMoa2118542.
   PubMed Web of Science ®Google Scholar
• Register of medicinal products authorized for use in the Republic of Bulgaria: Bulgarian Drug Agency; 2023. Available from: https://www.bda.bg/en.
   Google Scholar
• Fu Y, Zhao J, Han P, et al. Cost-effectiveness of COVID-19 vaccination: a systematic review. J Evid Based Med. 2023;16(2):152–165.
   PubMedGoogle Scholar
• Li Q, Wang Y, Sun Q, et al. Immune response in COVID-19: what is next? Cell Death Differ. 2022;29(6):1107–1122. doi: 10.1038/s41418-022-01015-x.
   PubMed Web of Science ®Google Scholar
• WHO. COVID-19 advice for the public: getting vaccinated: WHO. 2023. Available from: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/covid-19-vaccines/advice.
   Google Scholar
• Park HJ, Gonsalves GS, Tan ST, et al. Comparing frequency of booster vaccination to prevent severe COVID-19 by risk group in the United States. Nat Commun. 2024;15(1):1883. doi: 10.1038/s41467-024-45549-9.
   PubMed Web of Science ®Google Scholar
• Carabelli AM, Peacock TP, Thorne LG, et al. SARS-CoV-2 variant biology: immune escape, transmission and fitness. Nat Rev Microbiol. 2023;21(3):162–177. 3/01 doi: 10.1038/s41579-022-00841-7.
   PubMed Web of Science ®Google Scholar
• Abdel-Qader DH, Abdel-Qader H, Silverthorne J, et al. Real-world effectiveness of four types of COVID-19 vaccines. Vaccines (Basel). 2023;11(5):985. PubMed PMID37243089Pubmed Central PMCID: PMC10224211. Epub 2023/05/27. eng. doi: 10.3390/vaccines11050985.
   PubMed Web of Science ®Google Scholar