Eveline Toth

Publications (5)47.73 Total impact

• Article: The largest measles epidemic in North America in a decade--Quebec, Canada, 2011: Contribution of susceptibility, serendipity and super-spreading events on elimination.

  Gaston De Serres, France Markowski, Eveline Toth, Monique Landry, Danielle Auger, Marlène Mercier, Philippe Bélanger, Bruno Turmel, Horacio Arruda, Nicole Boulianne, Brian J Ward, Danuta M Skowronski
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  ABSTRACT: Introduction. We describe the largest measles epidemic in North America in the last decade occurring in the population of Quebec, Canada in 2011 where one- and two-dose vaccine coverage among children 3years of age were 95-97% and 90%, respectively, with 3-5% unvaccinated.Methods. Cases identified through passive surveillance and outbreak investigation were contacted to describe clinical course, vaccination status and possible source of infection.Results. There were 21 measles importations and 725 cases. A super-spreading event triggered by one importation resulted in sustained transmission and 678 cases. The incidence per 100,000 was 9.1, highest in adolescents 12-17years old (75.6) comprising 56% of cases. Among adolescent cases, 22% had received two vaccine doses. Outbreak investigation showed this proportion to have been an under-estimate: active case-finding identified 130% more cases among two-dose recipients. Two-dose recipients had milder illness and significantly lower risk of hospitalization compared to unvaccinated or single-dose cases.Conclusion. A chance super-spreading event revealed an overall level of immunity barely above the elimination threshold when taking into account unexpected vulnerability in two-dose recipients. Unvaccinated individuals remain the immunization priority but a better understanding of susceptibility in two-dose recipients is needed to define effective interventions if elimination is to be achieved.
  The Journal of Infectious Diseases 12/2012; · 6.41 Impact Factor
• Article: Risk of Guillain-Barré syndrome following H1N1 influenza vaccination in Quebec.

  Philippe De Wals, Geneviève Deceuninck, Eveline Toth, Nicole Boulianne, Denis Brunet, Renée-Myriam Boucher, Monique Landry, Gaston De Serres
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  ABSTRACT: In fall 2009 in Quebec, Canada, an immunization campaign was launched against the 2009 influenza A(H1N1) pandemic strain, mostly using an AS03 adjuvant vaccine. By the end of the year, 57% of the 7.8 million residents had been vaccinated. To assess the risk of Guillain-Barré syndrome (GBS) following pandemic influenza vaccine administration. Population-based cohort study with follow-up over the 6-month period October 2009 through March 2010. The investigation was ordered by the chief medical officer of health in accordance with the Quebec Public Health Act. All acute care hospitals and neurology clinics in Quebec. Suspected and confirmed GBS cases reported by physicians, mostly neurologists, during active surveillance or identified in the provincial hospital summary discharge database. Medical records were reviewed and cases classified according to Brighton Collaboration definitions (categorized as level 1, 2, or 3, corresponding to criteria of decreasing certainty in diagnosis). Immunization status was verified and denominators were estimated from the provincial immunization registry (4.4 million vaccinated) and census data (total target population aged ≥6 months, 7.8 million), with a total of 3,623,046 person-years of observation. Relative and attributable risks were calculated using a Poisson model and the self-controlled case-series method. Over a 6-month period, 83 confirmed GBS cases were identified, including 71 Brighton level 1 through 3 cases. Twenty-five confirmed cases had been vaccinated against 2009 influenza A(H1N1) 8 or fewer weeks before disease onset, with most (19/25) vaccinated 4 or fewer weeks before onset. In the Poisson model, the age- and sex-adjusted relative risk was 1.80 (95% CI, 1.12-2.87) for all confirmed cases during the 8-week postvaccination period and was 2.75 (95% CI, 1.63-4.62) during the 4-week postvaccination period. Using the self-controlled case-series method, relative risk estimates during the 4-week postvaccination period were 3.02 (95% CI, 1.64-5.56) for all confirmed cases (n = 42) and 2.33 (95% CI, 1.19-4.57) for Brighton level 1 through 3 cases (n = 36). The number of GBS cases attributable to vaccination was approximately 2 per 1 million doses. There was no indication of an excess risk in persons younger than 50 years. In Quebec, the 2009 influenza A(H1N1) vaccine was associated with a small but significant risk of GBS. It is likely that the benefits of immunization outweigh the risks.
  JAMA The Journal of the American Medical Association 07/2012; 308(2):175-81. · 30.03 Impact Factor
• Article: Oculo-respiratory syndrome after influenza vaccination: trends over four influenza seasons.

  Gaston De Serres, Eveline Toth, Suzanne Ménard, Jean Luc Grenier, Renée Roussel, Michèle Tremblay, Monique Landry, Yves Robert, Louis Rochette, Danuta M Skowronski
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  ABSTRACT: Oculo-respiratory syndrome (ORS) following influenza vaccination was identified in Canada in 2000. This report describes trends of ORS reported during four consecutive seasons 2000, 2001, 2002 and 2003 in the province of Quebec, Canada. Data come from the vaccine-associated adverse event (VAAE) passive reporting system of the Province of Quebec. The rate of ORS reported per 100000 doses distributed declined from 46.6 in 2000 to 34.2, 20.6 and 9 in 2001, 2002 and 2003, respectively. There was no significant difference in rates for ORS between the two vaccines in use in Canada (Fluviral and Vaxigrip) both in 2001 and 2002. During the 4 years, incidence was highest in people aged 40-59 years and declined in older age groups. The clinical profile of ORS has remained remarkably stable over years. Overall, ocular, respiratory symptoms or facial edema were reported by 58%, 84% and 31% of patients, respectively, and 15% had symptoms including all three symptom categories. ORS lasted more than a week in 8-13% of the cases. ORS is an adverse event that occurred with both influenza vaccines used in Canada. Its frequency has declined substantially but is still present after 4 years. It constitutes a clinical entity distinct from anaphylactic allergy. Unlike anaphylaxis, ORS does not constitute an absolute contraindication to further doses.
  Vaccine 06/2005; 23(28):3726-32. · 3.77 Impact Factor
• Article: Oculo-respiratory syndrome following influenza vaccination: evidence for occurrence with more than one influenza vaccine.

  Gaston De Serres, Nicole Boulianne, Bernard Duval, Louis Rochette, Jean Luc Grenier, Renée Roussel, Danièle Donaldson, Michèle Tremblay, Eveline Toth, Suzanne Ménard, Monique Landry, Yves Robert
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  ABSTRACT: We assessed the occurrence of oculo-respiratory syndrome (ORS) following two influenza vaccines: Fluviral (Shire Biologics) or Vaxigrip (Aventis Pasteur). ORS was identified amongst 5.3 and 4.6% of recipients, respectively (P=0.54). With both vaccines, the risk of ORS was much greater in individuals who had ORS the previous year (2000) than in those without such history. In multivariate analysis, the odds ratio for ORS for patients with a prior history of ORS varied between 9.4 and 9.6 (P<0.001) whereas that comparing Fluviral and Vaxigrip varied between 1.5 and 1.9 (P=0.02-0.05). ORS is an adverse event that is present with more than one vaccine and may be present with any influenza vaccines to a greater or lesser degree.
  Vaccine 06/2003; 21(19-20):2346-53. · 3.77 Impact Factor
• Article: The clinical spectrum of the oculo-respiratory syndrome after influenza vaccination.

  Gaston De Serres, Jean Luc Grenier, Eveline Toth, Suzanne Ménard, Renée Roussel, Michèle Tremblay, Monique Douville Fradet, Monique Landry, Yves Robert, Danuta M Skowronski
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  ABSTRACT: Oculo-respiratory syndrome (ORS), a new influenza vaccine associated adverse event, was identified in 2000. The 2000 case definition (ORS-2000) required the presence of bilateral red eyes or respiratory symptoms or facial edema occurring between 2 and 24h following immunization and lasting <or=48 h. We compared clinical manifestations of cases outside these timelines. Cases were classified as ORS-early (onset <2 h after immunization), ORS-late (onset >24 h), ORS-persistors (duration >48 h).Overall, the distribution of symptoms was similar between ORS-2000 and other case categories. ORS-early and ORS-late had less ocular involvement, ORS-late and ORS-persistors had more cough and sore throat, ORS-early had more facial edema and ORS-late had less. In comparison to ORS-2000, ORS-early were younger whereas ORS-persistors and ORS-late were significantly older suggesting that clinical manifestations of ORS vary with age with a more rapid induction of symptoms in younger individuals and longer duration for older ones.
  Vaccine 06/2003; 21(19-20):2354-61. · 3.77 Impact Factor