Browsing by Author "Baguelin, Marc"
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- Different transmission patterns in the early stages of the influenza A(H1N1)v pandemic: a comparative analysis of 12 European countriesPublication . Flasche, Stefan; Hens, Niel; Boëlle, Pierre-Yves; Mossong, Joël; van Ballegooijen, W. Marijn; Nunes, Baltazar; Rizzo, Caterina; Popovici, Florin; Santa-Olalla, Patricia; Hrubá, Frantiska; Parmakova, Kremena; Baguelin, Marc; van Hoek, Albert Jan; Desenclos, Jean-Claude; Bernillon, Pascale; Cámara, Amparro Larrauri; Wallinga, Jacco; Asikainen, Tommi; White, Peter J.; Edmunds, W. JohnFollowing the emergence of a novel strain of influenza A(H1N1) in Mexico and the United States in April 2009, its epidemiology in Europe during the summer was limited to sporadic and localised outbreaks. Only the United Kingdom experienced widespread transmission declining with school holidays in late July. Using statistical modelling where applicable we explored the following causes that could explain this surprising difference in transmission dynamics: extinction by chance, differences in the susceptibility profile, age distribution of the imported cases, differences in contact patterns, mitigation strategies, school holidays and weather patterns. No single factor was able to explain the differences sufficiently. Hence an additive mixed model was used to model the country-specific weekly estimates of the effective reproductive number using the extinction probability, school holidays and weather patterns as explanatory variables. The average extinction probability, its trend and the trend in absolute humidity were found to be significantly negatively correlated with the effective reproduction number - although they could only explain about 3% of the variability in the model. By comparing the initial epidemiology of influenza A (H1N1) across different European countries, our analysis was able to uncover a possible role for the timing of importations (extinction probability), mixing patterns and the absolute humidity as underlying factors. However, much uncertainty remains. With better information on the role of these epidemiological factors, the control of influenza could be improved.
- Health and economic impact of seasonal influenza mass vaccination strategies in European settings: A mathematical modelling and cost-effectiveness analysisPublication . Sandmann, Frank; van Leeuwen, Edwin; Bernard-Stoecklin, Sibylle; Casado, Itziar; Castilla, Jesús; Domegan, Lisa; Gherasim, Alin; Hooiveld, Mariëtte; Kislaya, Irina; Larrauri, Amparo; Levy-Bruhl, Daniel; Machado, Ausenda; Marques, Diogo; Martínez-Baz, Iván; Mazagatos, Clara; McMenamin, Jim; Meijer, Adam; Murray, Josephine; Nunes, Baltazar; O'Donnell, Joan; Reynolds, Arlene; Thorrington, Dominic; Pebody, Richard; Baguelin, MarcIntroduction: Despite seasonal influenza vaccination programmes in most countries targeting individuals aged ≥ 65 (or ≥ 55) years and high risk-groups, significant disease burden remains. We explored the impact and cost-effectiveness of 27 vaccination programmes targeting the elderly and/or children in eight European settings (n = 205.8 million). Methods: We used an age-structured dynamic-transmission model to infer age- and (sub-)type-specific seasonal influenza virus infections calibrated to England, France, Ireland, Navarra, The Netherlands, Portugal, Scotland, and Spain between 2010/11 and 2017/18. The base-case vaccination scenario consisted of non-adjuvanted, non-high dose trivalent vaccines (TV) and no universal paediatric vaccination. We explored i) moving the elderly to "improved" (i.e., adjuvanted or high-dose) trivalent vaccines (iTV) or non-adjuvanted non-high-dose quadrivalent vaccines (QV); ii) adopting mass paediatric vaccination with TV or QV; and iii) combining the elderly and paediatric strategies. We estimated setting-specific costs and quality-adjusted life years (QALYs) gained from the healthcare perspective, and discounted QALYs at 3.0%. Results: In the elderly, the estimated numbers of infection per 100,000 population are reduced by a median of 261.5 (range across settings: 154.4, 475.7) when moving the elderly to iTV and by 150.8 (77.6, 262.3) when moving them to QV. Through indirect protection, adopting mass paediatric programmes with 25% uptake achieves similar reductions in the elderly of 233.6 using TV (range: 58.9, 425.6) or 266.5 using QV (65.7, 477.9), with substantial health gains from averted infections across ages. At €35,000/QALY gained, moving the elderly to iTV plus adopting mass paediatric QV programmes provides the highest mean net benefits and probabilities of being cost-effective in all settings and paediatric coverage levels. Conclusion: Given the direct and indirect protection, and depending on the vaccine prices, model results support a combination of having moved the elderly to an improved vaccine and adopting universal paediatric vaccination programmes across the European settings.
- Understanding differences in cervical cancer incidence in Western Europe: comparing Portugal and EnglandPublication . Mendes, Diana; Mesher, David; Pista, Angela; Baguelin, Marc; Jit, MarkCervical cancer incidence has decreased over time in England particularly after the introduction of organized screening. In Portugal, where opportunistic screening has been widely available with only slightly lower coverage than that of the organized programme in England, rates of cervical cancer have been higher than in England. We compared the burden of cervical cancer, risk factors and preventive interventions over time in both countries, to identify elements hindering the further decline in incidence and mortality in Portugal.