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Infectious Disorders - Drug Targets

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ISSN (Online): 2212-3989

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Review Article

Efficacy and Prolonged Safety of Haemophilus influenzae Type b Conjugate Vaccines

Author(s): Nishita Tripathi and Sayali Mukherjee*

Volume 24, Issue 5, 2024

Published on: 15 January, 2024

Article ID: e150124225640 Pages: 11

DOI: 10.2174/0118715265269877231117070051

Price: $65

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Abstract

Objective: The purpose of this study was to find data proving the influence of the Haemophilus influenzae type b (Hib) conjugate vaccination on the frequency of invasive Hib illness.

Methodology: A systematic literature search was conducted on the PubMed database to identify peerreviewed publications pertaining to the epidemiology of Haemophilus influenzae meningitis, both before and after the introduction of Haemophilus influenzae type b (Hib) conjugate vaccines. The search query employed a combination of relevant keywords, including "invasive," "Haemophilus," "influenzae," "meningitis," and specific serotype b (Hib). Additionally, terms related to epidemiology, burden, risk factors, impact, Hib vaccine, Hib conjugate vaccine, combination vaccine, vaccine production, efficacy, immunisation coverage, surveillance, review, clinical aspects, outcomes, and various age groups (adults and children) were incorporated.

Result: The search encompassed articles published till now. Subsequently, relevant research papers concerning Haemophilus influenzae meningitis were subjected to a comprehensive review and analysis.

Conclusion: The Hib conjugate vaccination has shown to be extremely effective when administered to the entire population. However, changes to the immunisation protocol appear to be required in order to effectively manage invasive Hib illness.

Keywords: Haemophilus influenzae type b, conjugate vaccine, safety, efficacy, invasive Hib illness, H. influenzae meningitis.

Graphical Abstract

[1]
Khattak ZE, Anjum F. Haemophilus influenzae infection.In: StatPearls. Treasure Island, FL: StatPearls Publishing 2023. https://www.ncbi.nlm.nih.gov/books/NBK562176/ Updated 2023 Apr 27 Internet
[2]
Arístegui J, Usonis V, Coovadia H, et al. Facilitating the who expanded program of immunization: the clinical profile of a combined diphtheria, tetanus, pertussis, hepatitis b and Haemophilus influenzae type b vaccine. Int J Infect Dis 2003; 7(2): 143-51.
[http://dx.doi.org/10.1016/S1201-9712(03)90011-7] [PMID: 12839717]
[3]
Mallet E, Belohradsky BH, Lagos R, et al. A liquid hexavalent combined vaccine against diphtheria, tetanus, pertussis, poliomyelitis, Haemophilus influenzae type B and hepatitis B: review of immunogenicity and safety. Vaccine 2004; 22(11-12): 1343-57.
[http://dx.doi.org/10.1016/j.vaccine.2003.09.039] [PMID: 15063556]
[4]
Levine OS, Ortiz E, Contreras R, et al. Cost-benefit analysis for the use of Haemophilus influenzae type b conjugate vaccine in Santiago, Chile. Am J Epidemiol 1993; 137(11): 1221-8.
[http://dx.doi.org/10.1093/oxfordjournals.aje.a116624] [PMID: 8322763]
[5]
Lagos R, Levine OS, Avendaño A, Horwitz I, Levine MM. The introduction of routine Haemophilus influenzae type b conjugate vaccine in Chile: a framework for evaluating new vaccines in newly industrializing countries. Pediatr Infect Dis J 1998; 17(9) (Suppl.): S139-48.
[http://dx.doi.org/10.1097/00006454-199809001-00010] [PMID: 9781748]
[6]
Mahoney R. Policy analysis: An essential research tool for the introduction of vaccines in developing countries. J Health Popul Nutr 2004; 22(3): 331-7.
[PMID: 15609786]
[7]
Watt JP, Levine OS, Santosham M. Global reduction of Hib disease: what are the next steps? Proceedings of the meeting Scottsdale, Arizona, September 22-25, 2002. J Pediatr 2003; 143(6) (Suppl.): S163-87.
[http://dx.doi.org/10.1067/S0022-3476(03)00576-6] [PMID: 14657805]
[8]
Ulanova Marina . Global epidemiology of invasive Haemophilus influenzae type a disease: Do we need a new vaccine? J Vaccines 2013; Article ID 941461. 14 pages, 2013
[http://dx.doi.org/10.1155/2013/941461]
[9]
World Health Organization.Estimating the local burden of Haemophilus influenzae type b Hib disease preventable by vaccination. Geneva: WHO 2001. WHO/V&B/01.27
[10]
Di Fabio JL, de Quadros C. Considerations for combination vaccine development and use in the developing world. Clin Infect Dis 2001; 33(s4) (Suppl. 4): S340-5.
[http://dx.doi.org/10.1086/322571] [PMID: 11709770]
[11]
World Health Organization Countries using Hib vaccine in their national infant immunization system as of December 2003.
[12]
Levine OS, Schwartz B, Pierce N, Kane M. Development, evaluation and implementation of Haemophilus influenzae type b vaccines for young children in developing countries: current status and priority actions. Pediatr Infect Dis J 1998; 17(9) (Suppl.): S95-S113.
[http://dx.doi.org/10.1097/00006454-199809001-00003] [PMID: 9781741]
[13]
Feikin DR, Nelson CB, Watt JP, Mohsni E, Wenger JD, Levine OS. Rapid assessment tool for Haemophilus influenzae type b disease in developing countries. Emerg Infect Dis 2004; 10(7): 1270-6.
[http://dx.doi.org/10.3201/eid1007.030737] [PMID: 15324548]
[14]
Peltola H. Worldwide Haemophilus influenzae type b disease at the beginning of the 21st century: global analysis of the disease burden 25 years after the use of the polysaccharide vaccine and a decade after the advent of conjugates. Clin Microbiol Rev 2000; 13(2): 302-17.
[http://dx.doi.org/10.1128/CMR.13.2.302] [PMID: 10756001]
[15]
Peltola H. Spectrum and burden of severe Haemophilus influenzae type b diseases in Asia. Bull World Health Organ 1999; 77(11): 878-87.
[PMID: 10612883]
[16]
Gessner B. Worldwide variation in the incidence of Haemophilus influenzae type b meningitis and its association with ampicillin resistance. Eur J Clin Microbiol Infect Dis 2002; 21(2): 79-87.
[http://dx.doi.org/10.1007/s10096-001-0667-z] [PMID: 11939404]
[17]
Kim J, Jang YT, Kim JD, et al. Incidence of Haemophilus influenzae type b and other invasive diseases in South Korean children. Vaccine 2004; 22(29-30): 3952-62.
[http://dx.doi.org/10.1016/j.vaccine.2004.04.003] [PMID: 15364444]
[18]
Saha SK, Baqui AH, Darmstadt GL, et al. Invasive Haemophilus influenzae type b diseases in Bangladesh, with increased resistance to antibiotics. J Pediatr 2005; 146(2): 227-33.
[http://dx.doi.org/10.1016/j.jpeds.2004.09.007] [PMID: 15689914]
[19]
Gessner BD, Sutanto A, Linehan M, et al. Incidences of vaccine-preventable Haemophilus influenzae type b pneumonia and meningitis in Indonesian children: Hamlet-randomised vaccine-probe trial. Lancet 2005; 365(9453): 43-52.
[http://dx.doi.org/10.1016/S0140-6736(04)17664-2] [PMID: 15643700]
[20]
Lagos R, Horwitz I, Toro J, et al. Large scale, postlicensure, selective vaccination of Chilean infants with PRP-T conjugate vaccine: Practicality and effectiveness in preventing invasive Haemophilus influenzae type b infections. Pediatr Infect Dis J 1996; 15(3): 216-22.
[http://dx.doi.org/10.1097/00006454-199603000-00008] [PMID: 8852909]
[21]
Weiss DPL, Coplan P, Guess H. Epidemiology of bacterial meningitis among children in Brazil, 1997-1998. Rev Saude Publica 2001; 35(3): 249-55.
[http://dx.doi.org/10.1590/S0034-89102001000300006] [PMID: 11486147]
[22]
Simões LL, Andrade AL, Laval CA, et al. [Impact of Haemophilus influenzae b (Hib) vaccination on meningitis in Central Brazil] Rev Saude Publica 2004; 38(5): 664-70.
[PMID: 15499437]
[23]
Gilsdorf JR. Hib vaccines: Their impact on Haemophilus influenzae type b disease. J Infect Dis 2021; 224(12) (Suppl. 4): S321-30.
[http://dx.doi.org/10.1093/infdis/jiaa537] [PMID: 34590133]
[24]
Kelly DF, Moxon ER, Pollard AJ. Haemophilus influenzae type b conjugate vaccines. Immunology 2004; 113(2): 163-74.
[http://dx.doi.org/10.1111/j.1365-2567.2004.01971.x] [PMID: 15379976]
[25]
Gomez PL, Robinson JM. Vaccine manufacturing. Plotkin’s Vaccines 2018; 51-60.e1.
[http://dx.doi.org/10.1016/B978-0-323-35761-6.00005-5]
[26]
2022. Hibtiter (diphtheria CRM197 protein conjugate): Uses, dosage, side effects, interactions, warning. RxList. https://www.rxlist.com/hibtiter-drug.htm#description Last updated on RxList: 10/12/2022
[27]
2020.https://www.rxlist.com/acthib-drug.htm ActHIB (haemophilus B conjugate vaccine): Uses, dosage, side effects, interactions, warning. RxList.
[28]
2022.https://www.rxlist.com/pedvaxhib-drug.htm Pedvax Hib (haemophilus B conjugate vaccine): Uses, dosage, side effects, interactions, warning. RxList.
[29]
Briere EC. Food and Drug Administration Approval for Use of Hiberix as a 3-Dose Primary Haemophilus influenzae Type b (Hib) Vaccination Series. MMWR Morb Mortal Wkly Rep 2016; 65(16): 418-9.
[http://dx.doi.org/10.15585/mmwr.mm6516a3] [PMID: 27124887]
[30]
World Health Organization. In: Inspection report for WHO. Geneva, Switzerland 2019.
[31]
2021.https://www.rxlist.com/pentacel-drug.htm Pentacel (tetanus toxoid conjugate): Uses, dosage, side effects, interactions, warning. RxList.
[32]
Oliver SE, Moore KL. Licensure of a diphtheria and tetanus toxoids and acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b conjugate, and hepatitis b vaccine, and guidance for use in infants. MMWR Morb Mortal Wkly Rep 2020; 69(5): 136-9.
[http://dx.doi.org/10.15585/mmwr.mm6905a5] [PMID: 32027629]
[33]
Perry CM. Meningococcal groups C and Y and haemophilus B tetanus toxoid conjugate vaccine (HibMenCY-TT; MenHibrix(®)): a review. Drugs 2013; 73(7): 703-13.
[http://dx.doi.org/10.1007/s40265-013-0048-9] [PMID: 23649970]
[34]
2023.https://www.rxlist.com/comvax-drug.htm Comvax (haemophilus b conjugate and hepatitis B vaccine): Uses, dosage, side effects, interactions, warning. RxList.
[35]
2022.https://www.rxlist.com/pediarix-drug.htm Pediarix (diphtheria, tetanus Toxoids and acellular pertussis adsorbed, hepatitis B and inactivated poliovirus vaccine): Uses, dosage, side effects, interactions, warning. RxList.
[36]
Easyfive-TT 2023. WHO - Prequalification of Medical Products (IVDs, Medicines, Vaccines and Immunization Devices, Vector Control).
[37]
Aloysia D’Cor N, Siddaiah P, Mohapatra S, et al. Safety and immunogenicity of a new formulation of a pentavalent DTwP-HepB-Hib vaccine in healthy Indian infants-A randomized study. PLoS One 2023; 18(8)e0284898
[http://dx.doi.org/10.1371/journal.pone.0284898] [PMID: 37582114]
[38]
Serum Institute of India - poliovac (PFS/SD) - poliomyelitis vaccine (inactivated) I.P. (n.d.-a). https://www.seruminstitute.com/product_ind_pentavac.php (Last accessed September 2023)
[39]
Kummeling I, Thijs C, Stelma F, Huber M, van den Brandt PA, Dagnelie PC. Diphtheria, pertussis, poliomyelitis, tetanus, and Haemophilus influenzae type b vaccinations and risk of eczema and recurrent wheeze in the first year of life: The KOALA Birth Cohort Study. Pediatrics 2007; 119(2): e367-73.
[http://dx.doi.org/10.1542/peds.2006-1479] [PMID: 17272598]
[40]
Centre for Disease Control and Prevention (CDC). Chapter 2 In: Haemophilus influenzae invasive disease In: Manual for the surveillance of vaccine preventable diseases. National Center for Immunization and Respiratory Diseases 2019.
[41]
Griffiths UK, Clark A, Gessner B, et al. Dose-specific efficacy of Haemophilus influenzae type b conjugate vaccines: A systematic review and meta-analysis of controlled clinical trials. Epidemiol Infect 2012; 140(8): 1343-55.
[http://dx.doi.org/10.1017/S0950268812000957] [PMID: 22583474]
[42]
Slack M, Esposito S, Haas H, et al. Haemophilus influenzae type b disease in the era of conjugate vaccines: Critical factors for successful eradication. Expert Rev Vaccines 2020; 19(10): 903-17.
[http://dx.doi.org/10.1080/14760584.2020.1825948] [PMID: 32962476]
[43]
Zhang H, Garcia C, Yu W, et al. National and provincial impact and cost-effectiveness of Haemophilus influenzae type b conjugate vaccine in China: A modeling analysis. BMC Med 2021; 19(1): 181.
[http://dx.doi.org/10.1186/s12916-021-02049-7] [PMID: 34376214]
[44]
Rodrigues CMC, Plotkin SA. Impact of vaccines; health, economic and social perspectives. Front Microbiol 2020; 11: 1526.
[http://dx.doi.org/10.3389/fmicb.2020.01526] [PMID: 32760367]
[45]
Slack MPE. Long term impact of conjugate vaccines on Haemophilus influenzae meningitis: Narrative review. Microorganisms 2021; 9(5): 886.
[http://dx.doi.org/10.3390/microorganisms9050886] [PMID: 33919149]
[46]
Collins S, Ramsay M, Campbell H, Slack MPE, Ladhani SN. Invasive Haemophilus influenzae type b disease in England and Wales: Who is at risk after 2 decades of routine childhood vaccination? Clin Infect Dis 2013; 57(12): 1715-21.
[http://dx.doi.org/10.1093/cid/cit579] [PMID: 24076970]
[47]
Laval CAB, Pimenta FC, Andrade JG, Andrade SS, Andrade ALSS. Progress towards meningitis prevention in the conjugate vaccines era. Braz J Infect Dis 2003; 7(5): 315-24.
[http://dx.doi.org/10.1590/S1413-86702003000500006] [PMID: 14552741]
[48]
Ruocco G, Curto S, Savio M, Laurani H, Frocht R. Vacunación contra Haemophilus influenzae tipo b en el Uruguay: Experiencia e impacto. Rev Panam Salud Publica 1999; 5(3): 197-9.
[http://dx.doi.org/10.1590/S1020-49891999000300021] [PMID: 10355316]
[49]
Nascimento-Carvalho CM, de Andrade AL. Haemophilus influenzae type b vaccination: long-term protection. J Pediatr 2006; 82(3) (Suppl.): S109-14.
[http://dx.doi.org/10.1590/S0021-75572006000400013] [PMID: 16826309]
[50]
Agudelo CI, Muñoz N, De la Hoz F. Rapid assessment of the impact of Haemophilus influenzae vaccine serotype b in Colombia Rev Panam Salud Publica 2000; 8(3): 181-4.
[http://dx.doi.org/10.1590/S1020-49892000000800005] [PMID: 11036428]
[51]
Freitas H. Meningite por Haemophilus influenzae b no Distrito Federal Aspectos epidemiológicos e impacto após introdução da vacina [dissertação]. In: Brasília: Universidade de Brasília. 2000.
[52]
Takemura NS, Andrade SM. Haemophilus influenzae type b meningitis in the state of Paraná, Brazil. J Pediatr 2001; 77(5): 387-92.
[http://dx.doi.org/10.2223/JPED.280] [PMID: 14647843]
[53]
Dickinson FO, Pérez AE, Galindo MA, Quintana I. Impacto de la vacunación contra Haemophilus influenzae tipo b en Cuba. Rev Panam Salud Publica 2001; 10(3): 169-73.
[http://dx.doi.org/10.1590/S1020-49892001000900004] [PMID: 11702372]
[54]
Díaz PJM, Catalán NL, Urrutia LMT, et al. Tendencias en la etiología de la meningitis bacteriana aguda en niños chilenos, período 1989-1998.: Impacto de la vacuna anti-H influenzae tipo b (Hib). Rev Med Chil 2001; 129(7): 719-26.
[http://dx.doi.org/10.4067/S0034-98872001000700003] [PMID: 11552439]
[55]
Ribeiro GS, Reis JN, Cordeiro SM, et al. Prevention of Haemophilus influenzae type b (Hib) meningitis and emergence of serotype replacement with type a strains after introduction of Hib immunization in Brazil. J Infect Dis 2003; 187(1): 109-16.
[http://dx.doi.org/10.1086/345863] [PMID: 12508153]
[56]
Kmetzsch CI, Schermann MT, Santana JCB, et al. Occurrence of Haemophylus influenzae B meningitis after the implementation of a mass vaccination program. J Pediatr 2003; 79(6): 530-6.
[http://dx.doi.org/10.2223/JPED.1114] [PMID: 14685451]
[57]
Delahoz F, Higuera AB, Di Fabio JL, et al. Effectiveness of Haemophilus influenzae type b vaccination against bacterial pneumonia in Colombia. Vaccine 2004; 23(1): 36-42.
[http://dx.doi.org/10.1016/j.vaccine.2004.05.017] [PMID: 15519705]
[58]
Review panel on Haemophilus influenzae type b (Hib) disease burden in Bangladesh, Indonesia and other Asian countries, Bangkok, 28-29 January 2004. Wkly Epidemiol Rec 2004; 79(18): 173-5.
[PMID: 15168565]
[59]
Nelson CM, Sutanto A, Gessner BD, Suradana IG, Steinhoff MC, Arjoso S. Age- and cause-specific childhood mortality in Lombok, Indonesia, as a factor for determining the appropriateness of introducing Haemophilus influenzae type b and pneumococcal vaccines. J Health Popul Nutr 2000; 18(3): 131-8.
[PMID: 11262765]
[60]
Jones G, Steketee RW, Black RE, Bhutta ZA, Morris SS. How many child deaths can we prevent this year? Lancet 2003; 362(9377): 65-71.
[http://dx.doi.org/10.1016/S0140-6736(03)13811-1] [PMID: 12853204]
[61]
Andrade ALSS, Afonso ET, Silva SA, Neto OLM, Marques SM, Martelli CMT. Invasive Disease-related mortality among children before and after the introduction of the Haemophilus influenzae type B conjugate vaccine in Brazil. Int J Infect Dis 2004; 8 (Suppl. 1): 75.
[62]
Garner D, Weston V. Effectiveness of vaccination for Haemophilus influenzae type b. Lancet 2003; 361(9355): 395-6.
[http://dx.doi.org/10.1016/S0140-6736(03)12385-9] [PMID: 12573380]
[63]
Trotter CL, Ramsay ME, Slack MP. Rising incidence of Haemophilus influenzae type b disease in England and Wales indicates a need for a second catch-up vaccination campaign. Commun Dis Public Health 2003; 6(1): 55-8.
[PMID: 12736974]
[64]
van Alphen L, Spanjaard L, van der Ende A, Schuurman I, Dankert J. Effect of nationwide vaccination of 3-month-old infants in The Netherlands with conjugate Haemophilus influenzae type b vaccine: High efficacy and lack of herd immunity. J Pediatr 1997; 131(6): 869-73.
[http://dx.doi.org/10.1016/S0022-3476(97)70035-0] [PMID: 9427892]
[65]
Rijkers GT, Vermeer-de Bondt PE, Spanjaard L, Breukels MA, Sanders EAM. Return of Haemophilus influenzae type b infections. Lancet 2003; 361(9368): 1563-4.
[http://dx.doi.org/10.1016/S0140-6736(03)13201-1] [PMID: 12737898]
[66]
Ramsay ME, McVernon J, Andrews NJ, Heath PT, Slack MP. Estimating Haemophilus influenzae type b vaccine effectiveness in England and Wales by use of the screening method. J Infect Dis 2003; 188(4): 481-5.
[http://dx.doi.org/10.1086/376997] [PMID: 12898433]
[67]
Trotter CL, McVernon J, Andrews NJ, Burrage M, Ramsay ME. Antibody to Haemophilus influenzae type b after routine and catch-up vaccination. Lancet 2003; 361(9368): 1523-4.
[http://dx.doi.org/10.1016/S0140-6736(03)13172-8] [PMID: 12737867]
[68]
McVernon J, Andrews N, Slack MPE, Ramsay ME. Risk of vaccine failure after Haemophilus influenzae type b (Hib) combination vaccines with acellular pertussis. Lancet 2003; 361(9368): 1521-3.
[http://dx.doi.org/10.1016/S0140-6736(03)13171-6] [PMID: 12737866]
[69]
Sarangi J, Cartwright K, Stuart J, Brookes S, Morris R, Slack M. Invasive Haemophilus influenzae disease in adults. Epidemiol Infect 2000; 124(3): 441-7.
[http://dx.doi.org/10.1017/S0950268899003611] [PMID: 10982068]
[70]
McVernon J, Trotter CL, Slack MPE, Ramsay ME. Trends in Haemophilus influenzae type b infections in adults in England and Wales: Surveillance study. BMJ 2004; 329(7467): 655-8.
[http://dx.doi.org/10.1136/bmj.329.7467.655] [PMID: 15374916]
[71]
Käyhty R, Peltola H, Karanko V, Mäkelä PH. The protective level of serum antibodies to the capsular polysaccharide of Haemophilus influenzae type b. J Infect Dis 1983; 147(6): 1100.
[http://dx.doi.org/10.1093/infdis/147.6.1100] [PMID: 6602191]
[72]
Heath PT, Booy R, Azzopardi HJ, et al. Antibody concentration and clinical protection after Hib conjugate vaccination in the United Kingdom. JAMA 2000; 284(18): 2334-40.
[http://dx.doi.org/10.1001/jama.284.18.2334] [PMID: 11066183]
[73]
Barbour ML, Mayon-White RT, Coles C, Crook DWM, Moxon ER. The impact of conjugate vaccine on carriage of Haemophilus influenzae type b. J Infect Dis 1995; 171(1): 93-8.
[http://dx.doi.org/10.1093/infdis/171.1.93] [PMID: 7798687]
[74]
McVernon J, Mitchison NA, Moxon ER. T helper cells and efficacy of Haemophilus influenzae type b conjugate vaccination. Lancet Infect Dis 2004; 4(1): 40-3.
[http://dx.doi.org/10.1016/S1473-3099(03)00859-4] [PMID: 14720567]
[75]
Eskola J, Ward J, Dagan R, Goldblatt D, Zepp F, Siegrist CA. Combined vaccination of Haemophilus influenzae type b conjugate and diphtheria-tetanus-pertussis containing acellular pertussis. Lancet 1999; 354(9195): 2063-8.
[http://dx.doi.org/10.1016/S0140-6736(99)04377-9] [PMID: 10636384]
[76]
Fitzgerald M, Canny M, O’Flanagan D. Vaccination catch-up campaign in response to recent increase in Hib infection in Ireland. Euro Surveill 2005; 10(9)E050929.2
[PMID: 16788239]
[77]
American academy of pediatrics. Recommended childhood and adolescent immunization schedule United States In: Pickering LK, editor 2003 red book: . report of the Committee on Infectious Diseases 26th ed Elk Grove Village: American Academy of Pediatrics; 2003; p. 24.
[78]
World Health Organization (n.d.). Immunization coverage https://www.who.int/news-room/fact-sheets/detail/immunization-coverage Global immunization coverage 2022 Geneva
[79]
Wahl B, O’Brien KL, Greenbaum A, et al. Burden of Streptococcus pneumoniae and Haemophilus influenzae type b disease in children in the era of conjugate vaccines: Global, regional, and national estimates for 2000–15. Lancet Glob Health 2018; 6(7): e744-57.
[http://dx.doi.org/10.1016/S2214-109X(18)30247-X] [PMID: 29903376]
[80]
Statista (2023) India: Share of Hib3 immunization coverage 2022.

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