Talk:Epidemiological modelling

Discussions

Argument moved from Talk:Economic evaluation:

--K3 : In the latest published FinIP data for pneumonia the data seem to show a higher than expected effeciveness for PCV10. We want to suggest that this data should be cosidered in light of a recent study in Sweden where PCV10 and PCV13 are both used in a real life setting in the same healthcare system. From this study, based on the Swedish National Inpatient Registry held by the National Board of Health and Welfare, it was found that PCV13 has significanlty lower pneumonia rates in infants and that PCV13 may save more in-patient cost due to pneumonia in infants compared to PCV10. Ref. Berglund A., Ekelund M., Nyman L., poster from ISPPD-9. --Pfizer Oy, 2014-08-27 13:47:39 - R upload in Economic evaluation

About Question:

• "The focus is on the incidence of invasive pneumococcal disease (IPD) cases in different age groups covering the whole population."

⇤# : Because the epidemiological model neglects the benefits of prevention of respiratory infection episodes, which effectively represent majority of the vaccine preventable disease burden (e.g. Palmu et al, ESPID, 2014), the outcomes are considered insufficient to inform the cost effectiveness analyses, unless supplemented with estimates for reductions in the respiratory illness, including pneumonia and acute otitis media endpoint. -- GSK 12:33, 3 September 2014 (UTC)

• "The coverage of vaccination and vaccine efficacy against carriage are assumed to be high enough to justify the assumption of complete elimination of vaccine-type carriage among both the vaccinated and also, due to substantial herd effects, among the unvaccinated members of the population."

⇤# : The assumption that vaccine type (VT) disease will be reduced to zero, at a steady state, in children, should be extended to VT-related types, where effectiveness has been demonstrated.

For adults and elderly, a recent review by Feikin et al, Plos Medicine, 2013, which has reviewed almost a decade of experience with PCVs in UMV has shown that while there was a dramatic reduction (nearly elimination) of VT/VT-related disease in children, in adults and elderly, the VT continue to cause disease years after implementation of the programme. Therefore, the assumption about complete elimination of VT disease in these age groups, even at a steady state, is not supported by available data.

Assuming the adult disease is reduced to zero would be a gross overestimation of what can be realistically expected from a PCV programme based on the experience with PCVs so far. The assumption should be therefore adjusted based on the findings reported by Feikin et al, Plos Medicine, 2013, except where there is clear evidence suggesting no impact of the vaccine on nasopharyngeal carriage for a particular serotype. --GSK 12:33, 3 September 2014 (UTC)

• "Vaccine-type carriage will be completely replaced by carriage of the non-vaccine types whose disease causing potential is not altered by vaccination."

⇤# : There is some uncertainty with respect to the assumption of the extent of replacement for respective vaccine formulations (e.g Vesikari, ECCMID, 2013, Dagan, CID, 2013). Because this could extensively impact on the outcomes of the model, this uncertainty should be acknowledged and preferentially also be reflected in the weight which is attributed to the outcomes of the modelling in the award criteria. --GSK 12:33, 3 September 2014 (UTC)

• "The replacement model was built to reflect the accumulated 15 year long experience on use of pneumococcal conjugate vaccines worldwide and the related scientific research activity."

--# : Given the limitations and uncertainties around the assumptions of the model, especially on the replacement and consecutively net impact of PCVs in adults and elderly, as highlighted in the previous comments, it should be considered to take a conservative approach and assume similar replacement in disease and consequently similar net effect in adults and elderly with both formulations, that was observed with the first generation PCV, as a base case of the model. --GSK 12:33, 3 September 2014 (UTC)