The effectiveness of the influenza vaccine was rated as “low to moderate” during the 2012-13 season. And according to the preliminary results of a Spanish study, the 2013-2014 vaccine would be even less effective.
The effectiveness of the influenza vaccine was “low to moderate” during the 2012-13 season! This is the finding of a French study published a few days ago by the journal of the European Center for Disease Prevention and Control (ECDC) Eurosurveillance, and resumed by the medical press agency (APM). As every year, the evaluation of vaccine efficacy is carried out as part of the multicenter case-control study I-MOVE initiated by the ECDC. Preliminary results for the 2012-13 season, published in February 2013, suggested an overall efficiency of 50%. But the latter would in fact be “lower”, according to Esther Kissling, of the company EpiConcept in Paris, and her colleagues who carried out an analysis on samples taken in seven European countries (France, Germany, Ireland, Poland, Portugal, Romania and Spain).
The vaccine had an overall efficacy of 47%
These scientists had data on 7,954 patients with influenza-like illness or acute respiratory infection. After adjustment, the team established that during the 2012-2013 season, the vaccine reduced the risk of influenza B by 49%, that of influenza A (H1N1) by 50% and that of influenza A (H3N2) by 42%.
Moreover, it is in the 15-59 age group that the vaccine provided the best level of protection. In the end, the authors ask that this efficiency be improved in order to reach “acceptable levels of protection”.
These scientists had data on 7,954 patients with influenza-like illness or acute respiratory infection. After adjustment, the team established that during the 2012-2013 season, the vaccine reduced the risk of influenza B by 49%, that of influenza A (H1N1) by 50% and that of influenza A (H3N2) by 42%.
Moreover, it is in the 15-59 age group that the vaccine provided the best level of protection. In the end, the authors ask that this efficiency be improved in order to reach “acceptable levels of protection”.
Even worse for the 2013-2014 season
And the 2013-14 vaccine could be even less effective! This is what a Spanish study carried out with preliminary data provided as part of the I-MOVE study suggests: samples taken between December 9, 2013 and January 26, 2014.
The collection of these preliminary data was made possible because “Spain was one of the first European countries affected by the influenza epidemic this season”, as the lead author of the study Jesus Castilla explains ( Institute of Public Health of Navarre) in comments reported by the APM. Thus, among the 430 cases of influenza infection confirmed in the laboratory, 23% were immunized with the 2013-14 vaccine against 33% among the negative controls. This suggests that the vaccine reduces the risk of getting the flu by just 24%.
Worse still, among those 65 and over the effectiveness was only 11%, against 39% among the youngest.
Finally, an analysis by influenza strain suggests that the vaccine was more protective against influenza A (H1N1) viruses than against A (H3N2): 40% against 13%.
And this latest information is good news since this season in France, A (H1N1) viruses (58.6%) are circulating a little more than A (H3N2), according to the last weekly bulletin published on Wednesday by the network of regional groups. observation of influenza (Grog).
And the 2013-14 vaccine could be even less effective! This is what a Spanish study carried out with preliminary data provided as part of the I-MOVE study suggests: samples taken between December 9, 2013 and January 26, 2014.
The collection of these preliminary data was made possible because “Spain was one of the first European countries affected by the influenza epidemic this season”, as the lead author of the study Jesus Castilla explains ( Institute of Public Health of Navarre) in comments reported by the APM. Thus, among the 430 cases of influenza infection confirmed in the laboratory, 23% were immunized with the 2013-14 vaccine against 33% among the negative controls. This suggests that the vaccine reduces the risk of getting the flu by just 24%.
Worse still, among those 65 and over the effectiveness was only 11%, against 39% among the youngest.
Finally, an analysis by influenza strain suggests that the vaccine was more protective against influenza A (H1N1) viruses than against A (H3N2): 40% against 13%.
And this latest information is good news since this season in France, A (H1N1) viruses (58.6%) are circulating a little more than A (H3N2), according to the last weekly bulletin published on Wednesday by the network of regional groups. observation of influenza (Grog).
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