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Is a dose of 17D vaccine in the current context of Yellow Fever enough?

Dear Editor,

The availability of the effective 17D vaccine as well as an eradication program of Aedes aegypti dramatically decreased the urban Yellow Fever (YF) incidence in Americas.11 Vasconcelos PF. Single shot of 17D vaccine may not confer life-long protection against yellow fever. Mem Inst Oswaldo Cruz. 2018;113(2):135-137.,22 Staples JE, Monath TP. Yellow fever: 100 years of discovery. JAMA. 2008;300(8):960-962. However, in the last decades, the YF transmission was reported outside endemic area (Amazon region), with extension of viral circulation toward to densely populated and highly Aedes-infested regions and low vaccination coverage.33 Monath TP, Vasconcelos PF. Yellow fever. J Clin Virol. 2015;64:160-173.

4 Romano AP, Costa ZG, Ramos DG, et al. Yellow Fever outbreaks in unvaccinated populations, Brazil, 2008-2009. PLoS Negl Trop Dis. 2014;8(3):e2740.
-55 Carvalho RG, Lourenço-de-Oliveira R, Braga IA. Updating the geographical distribution and frequency of Aedes albopictus in Brazil with remarks regarding its range in the Americas. Mem Inst Oswaldo Cruz. 2014;109(6):787-796.

Since 1990s, Yellow Fever virus (YFV) have been extending its traditional endemic area toward to Southern and Southeastern regions in Brazil.44 Romano AP, Costa ZG, Ramos DG, et al. Yellow Fever outbreaks in unvaccinated populations, Brazil, 2008-2009. PLoS Negl Trop Dis. 2014;8(3):e2740. From July 2017, to epidemiological week 2, 2018, 470 YF cases were suspected in Brazil, 35 confirmed, and 20 deaths, with 411 epizootic confirmed.66 Brazil. Monitoramento do Período Sazonal da Febre Amarela, Brasil – 2017/2018. Informe n. 9. Brasilia: Ministério da Saúde; 2018:11.

Besides, the susceptibility and competence of Ae. aegypti and Aedes albopictus to YFV transmission had been demonstrated and they can become active vectors in YF reemergence77 Couto-Lima D, Madec Y, Bersot MI, et al. Potential risk of re-emergence of urban transmission of Yellow Fever virus in Brazil facilitated by competent Aedes populations. Sci Rep. 2017;7(1):4848. in YFV-free regions. The vector may be found in more than 130 countries with around 4 billion people at risk of introduction and spread of infection,88 Vasconcelos PF, Monath TP. Yellow fever remains a potential threat to public health. Vector Borne Zoonotic Dis. 2016;16(8):566-567. highlighting the concern for the future about the YFV outbreaks. Considering this epidemiological scenario, the area to vaccine coverage has been expanding, following the current recommendation of World Health Organization (WHO), which a single dose of 17D vaccine confers life-long protection against YF.99 Who. Vaccines and vaccination against yellow fever: WHO Position Paper, June 2013 - recommendations. Vaccine. 2015;33(1):76-77.

This decision is polemic for a series of reasons. Firstly, vaccine failures have already been demonstrated.33 Monath TP, Vasconcelos PF. Yellow fever. J Clin Virol. 2015;64:160-173.,1010 Belmusto-Worn VE, Sanchez JL, McCarthy K, et al. Randomized, double-blind, phase III, pivotal field trial of the comparative immunogenicity, safety, and tolerability of two yellow fever 17D vaccines (Arilvax and YF-VAX) in healthy infants and children in Peru. Am J Trop Med Hyg. 2005;72(2):189-197. Neutralizing antibodies levels may decrease significantly in adults and children eight and four years after primary vaccination, respectively,1111 Campi-Azevedo AC, Costa-Pereira C, Antonelli LR, et al. Booster dose after 10 years is recommended following 17DD-YF primary vaccination. Hum Vaccin Immunother. 2016;12(2):491-502.,1212 Cgfsoyfv. Duration of post-vaccination immunity against yellow fever in adults. Vaccine. 2014;32(39):4977-4984. and the immunogenicity in children is lower. Besides, following 17D vaccination, the T cell response is invoked, contributing to protection against wild-type YFV1313 Hepburn MJ, Kortepeter MG, Pittman PR, et al. Neutralizing antibody response to booster vaccination with the 17d yellow fever vaccine. Vaccine. 2006;24(15):2843-2849. and increasing the immune response. Studies have been also showing that even lower doses than standard may produce neutralizing antibodies levels.1414 Monath T, Gershman M, Staphles E, Barret A. Yellow fever vaccine. In: Plotkin S, Orenstein W, Offit P, eds. Vaccines. 6th ed. Saunders Elsevier; 2012:870–896.,1515 Roukens AH, Vossen AC, Bredenbeek PJ, van Dissel JT, Visser LG. Intradermally administered yellow fever vaccine at reduced dose induces a protective immune response: a randomized controlled non-inferiority trial. PLoS ONE. 2008;3(4):e1993. This strategy was already used in early epidemic in the Democratic Republic of Congo, as an option to stretch vaccine supplies,1616 Ahuka-Mundeke S, Casey RM, Harris JB, et al. Immunogenicity of fractional-dose vaccine during a yellow fever outbreak - preliminary report. N Engl J Med. 2018. which 98% (95% CI, 96-99) of seroconversion. All these factors may suggest a benefit of a booster in endemic or epidemic circumstances. However, it is important to consider that the method to measure antibody levels had low stringency (PRNT 50 rather than PRNT 80), which may result in detection of unspecific antibody. Besides, there is not correlation between protection and antibody titers.

In light of this information, the recommendation of a single dose of 17D vaccine might be not reasonable. We are suggesting the immediate vaccination to more than 90% of population (with fractional or full doses, respecting the contraindication), followed by vaccination campaign with full dose in the near future, and new studies about a single dose of 17D vaccine and response to fractional doses in different population and epidemiological context. Until then, due to vaccine failures already described, we believe at least two doses are recommended while as long as sufficient vaccines are available.

References

  • 1
    Vasconcelos PF. Single shot of 17D vaccine may not confer life-long protection against yellow fever. Mem Inst Oswaldo Cruz 2018;113(2):135-137.
  • 2
    Staples JE, Monath TP. Yellow fever: 100 years of discovery. JAMA 2008;300(8):960-962.
  • 3
    Monath TP, Vasconcelos PF. Yellow fever. J Clin Virol 2015;64:160-173.
  • 4
    Romano AP, Costa ZG, Ramos DG, et al. Yellow Fever outbreaks in unvaccinated populations, Brazil, 2008-2009. PLoS Negl Trop Dis 2014;8(3):e2740.
  • 5
    Carvalho RG, Lourenço-de-Oliveira R, Braga IA. Updating the geographical distribution and frequency of Aedes albopictus in Brazil with remarks regarding its range in the Americas. Mem Inst Oswaldo Cruz 2014;109(6):787-796.
  • 6
    Brazil. Monitoramento do Período Sazonal da Febre Amarela, Brasil – 2017/2018. Informe n. 9 Brasilia: Ministério da Saúde; 2018:11.
  • 7
    Couto-Lima D, Madec Y, Bersot MI, et al. Potential risk of re-emergence of urban transmission of Yellow Fever virus in Brazil facilitated by competent Aedes populations. Sci Rep 2017;7(1):4848.
  • 8
    Vasconcelos PF, Monath TP. Yellow fever remains a potential threat to public health. Vector Borne Zoonotic Dis 2016;16(8):566-567.
  • 9
    Who. Vaccines and vaccination against yellow fever: WHO Position Paper, June 2013 - recommendations. Vaccine 2015;33(1):76-77.
  • 10
    Belmusto-Worn VE, Sanchez JL, McCarthy K, et al. Randomized, double-blind, phase III, pivotal field trial of the comparative immunogenicity, safety, and tolerability of two yellow fever 17D vaccines (Arilvax and YF-VAX) in healthy infants and children in Peru. Am J Trop Med Hyg 2005;72(2):189-197.
  • 11
    Campi-Azevedo AC, Costa-Pereira C, Antonelli LR, et al. Booster dose after 10 years is recommended following 17DD-YF primary vaccination. Hum Vaccin Immunother 2016;12(2):491-502.
  • 12
    Cgfsoyfv. Duration of post-vaccination immunity against yellow fever in adults. Vaccine 2014;32(39):4977-4984.
  • 13
    Hepburn MJ, Kortepeter MG, Pittman PR, et al. Neutralizing antibody response to booster vaccination with the 17d yellow fever vaccine. Vaccine 2006;24(15):2843-2849.
  • 14
    Monath T, Gershman M, Staphles E, Barret A. Yellow fever vaccine. In: Plotkin S, Orenstein W, Offit P, eds. Vaccines 6th ed. Saunders Elsevier; 2012:870–896.
  • 15
    Roukens AH, Vossen AC, Bredenbeek PJ, van Dissel JT, Visser LG. Intradermally administered yellow fever vaccine at reduced dose induces a protective immune response: a randomized controlled non-inferiority trial. PLoS ONE 2008;3(4):e1993.
  • 16
    Ahuka-Mundeke S, Casey RM, Harris JB, et al. Immunogenicity of fractional-dose vaccine during a yellow fever outbreak - preliminary report. N Engl J Med. 2018.

Edited by

Editor: Marina Baquerizo

Publication Dates

  • Publication in this collection
    Jul-Sep 2018
Sociedade Brasileira de Microbiologia USP - ICB III - Dep. de Microbiologia, Sociedade Brasileira de Microbiologia, Av. Prof. Lineu Prestes, 2415, Cidade Universitária, 05508-900 São Paulo, SP - Brasil, Ramal USP 7979, Tel. / Fax: (55 11) 3813-9647 ou 3037-7095 - São Paulo - SP - Brazil
E-mail: bjm@sbmicrobiologia.org.br