Em artigo publicado na ultima semana na The Lancet, a pesquisadora Maira Aguiar foi enfática em afirmar:
"Dengvaxia também tem sido usada em um programa de vacinação em massa no Paraná, Brasil. Como não existem indícios de alta endemicidade nesta região, este programa deveria ser suspenso para minimizar a vacinação de indivíduos que não tiveram dengue.
Por questões de ética, ninguém deveria ter sido colocado individualmente em risco ao receber esta vacina mesmo que, em nível populacional, ela possa ter efeitos benéficos no número de internamentos pela doença."
Dengue vaccination: a more ethical approach is needed
Since 2016, we have discussed the risks behind the recommendation and use in mass vaccination programmes of Dengvaxia—a dengue vaccine produced by Sanofi Pasteur (Lyon, France)—without immunological pretesting.1, 2 By using differential equation models and statistical methods, my colleagues and I reassessed publicly available data from vaccine trials, and found a substantial reduction in the number of hospital admissions when Dengvaxia was given only to seropositive individuals (ie, those with a history of a previous infection from dengue virus), and a substantial increase in the number of hospital admissions over 5 years when administered without a previous population screening.3 More recently, we have found that an individual's serostatus before vaccination is the determinant of vaccine efficacy and its possible benefits.4, 5 These findings eventually led the manufacturer to do a new analysis of the available trial data, resulting in WHO changing its recommendations on this vaccine in December, 2017.6 Our efforts were recently acknowledged in an Editorial in The Lancet Infectious Diseases.7 I therefore wish to respond to a recent Correspondence in The Lancet by Tikki Pang and colleagues (Feb 17, p 654),8 written on behalf of the Asia Dengue Vaccine Advocacy Group (which has received unrestricted educational grants from Sanofi Pasteur).
Pang and colleagues agree that the risk of severe disease in vaccinated children naive to dengue virus is real,8 as confirmed by Sanofi Pasteur on Nov 29, 2017.6 However, the authors also propose continuation of the mass vaccination programme, with physicians informing parents that “the potential benefits of vaccination far outweigh the potential risks for their child on the basis of factors such as the endemicity level where they live and the age of the individual”.8 This approach is disturbing and unacceptable, especially after the latest public advice from WHO that “until a full review has been conducted, WHO recommends vaccination only in individuals with a documented past dengue infection”.9
Pang and colleagues have also, fortunately, mentioned that a reliable laboratory testing method to detect previous exposure is needed, and suggested that it could be discussed and implemented. I agree with the authors that a reliable laboratory test is urgently needed to identify seropositive individuals; however, this vaccine should only be used after finding seropositivity, and it is definitely not suitable for a mass immunisation programme that does not screen for previous dengue infection. As I have stated previously,5 as a matter of ethics, no one should have been put at risk by receiving this vaccine, even if, at the population level, this vaccine could provide a beneficial effect in terms of the number of hospital admissions and treatments.
Notably, Pang and colleagues mentioned that, in countries with a very high endemic rate of dengue virus, 90% of the population are likely to have been infected with the virus by adolescence. However, in the Philippines, children aged 9–11 years were the target for the mass vaccination programme. Dengvaxia is also being used in a mass vaccination programme in Paraná, Brazil. Since there is no indication of high endemicity in this region, this programme should also be suspended to minimise the vaccination of seronegative individuals.
It is frustrating to read such commentaries in which the authors cite a theologian from the 13th century to justify the risk of severe disease in seronegative individuals through receipt of the vaccine.
Getty Images/Dondi Tawatao/Contributor
*Maíra Aguiar
mafsantos@fc.ul.pt
Centre for Mathematics and Applications Faculty of
Sciences and Technology, Nova University of Lisbon,
2829-516 Caparica, Portugal
References
- Aguiar, M, Stollenwerk, N, and Halstead, SB. The risks behind Dengvaxia recommendation. Lancet Infect Dis. 2016; 16: 882–883
- Aguiar, M, Halstead, SB, and Stollenwerk, N. Consider stopping dengvaxia administration without immunological screening. Expert Rev Vaccines. 2017; 16: 301–302
- Aguiar, M, Stollenwerk, N, and Halstead, SB. The impact of the newly licensed dengue vaccine in endemic countries. PLoS Negl Trop Dis. 2016; 10: e0005179
- Aguiar, M and Stollenwerk, N. Dengvaxia efficacy dependency on serostatus: a closer look at more recent data. Clin Infect Dis. 2018; 66: 641–642
- Aguiar, M and Stollenwerk, N. Dengvaxia: age as surrogate for serostatus. Lancet Infect Dis. 2018;18: 245
- Sanofi. Sanofi updates information on dengue vaccine.http://mediaroom.sanofi.com/sanofi-updates-information-on-dengue-vaccine/Nov 29, 2017November 29, 2017
- The Lancet Infectious Diseases. The dengue vaccine dilemma. Lancet Infect Dis. 2018; 18: 123
- Pang, T, Gubler, D, Goh, DYT, and Ismail, Z. Dengue vaccination: a more balanced approach is needed. Lancet. 2018; 391: 654
- WHO. Updated questions and answers related to the dengue vaccine Dengvaxia® and its use.http://www.who.int/immunization/diseases/dengue/q_and_a_dengue_vaccine_dengvaxia_use/en/Dec 22, 2017December 22, 2017
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