Pandemic H1N1 influenza vaccine effective in 2009-10 flu season

Jan 11, 2011

One dose of the pandemic flu vaccines used in seven European countries conferred good protection against pandemic H1N1 influenza in the 2009-10 season, especially in people aged less than 65 years and in those without any chronic diseases. These findings from a study funded by the European Centre for Disease Prevention and Control (ECDC) and coordinated by EpiConcept, Paris, France, published in this week's PLoS Medicine, give an indication of the vaccine effectiveness for the influenza A (H1N1) 2009 strain included in the 2010-11 seasonal vaccines.

The authors conducted a multi-centre case-control study based on practitioner surveillance networks from seven countries—France, Hungary, Ireland, Italy, Romania, Portugal and Spain. Patients consulting a participating practitioner for influenza-like-illness had a nasal or throat swab taken within eight days of symptom onset. Individuals were considered vaccinated if they had received a dose of the more than 14 days before the date of onset of like illness and unvaccinated if they were not vaccinated at all or if the vaccine was given less than 15 days before the onset of symptoms.

The authors analysed pandemic influenza vaccination effectiveness in those vaccinated less than 8 days, those vaccinated between, and including, 8 and 14 days and those vaccinated more than 14 days before onset of symptoms compared to those who had never been vaccinated. The authors then used statistical models to measure the effectiveness of pandemic influenza vaccine according to three age groups (< 15, 15-64, and 65+ years of age) and the presence of chronic diseases. these results obtained during the late phase of the pandemic suggest good protection with the pandemic h1n1 vaccine (vaccine effectiveness estimates between 65% and 100%). the findings also suggest that the 2009-10 seasonal influenza vaccine (as opposed to the pandemic h1n1 vaccine) did not protect against pandemic h1n1 influenza illness.

The authors said: "The late availability of the pandemic vaccine and subsequent limited coverage with this vaccine hampered our ability to study vaccine benefits during the outbreak period." They added: "Future studies should include estimation of effectiveness of the new trivalent vaccine in the 2010-2011 season, when vaccination will occur before the influenza season starts."

Bruno C. Ciancio, senior influenza expert from ECDC – who conceived the idea of a European network to measure influenza vaccine effectiveness and collaborated to design the study– stressed: "This study showed the added value of collaboration at European level as concerns vaccine evaluation. In addition, the results obtained are especially important for European countries this season, considering that the predominant influenza strain currently circulating across Europe is influenza A (H1N1).''

Explore further: Molecular method classifies patients with polycythemia vera

More information: Valenciano M, Kissling E, Cohen J-M, Oroszi B, Barret A-S, et al. (2011) Estimates of Pandemic Influenza Vaccine Effectiveness in Europe, 2009-10: Results of Influenza Monitoring Vaccine Effectiveness in Europe (I-MOVE) Multicentre Case-Control Study. PLoS Med 8(1): e1000388. doi:10.1371/journal.pmed.1000388

add to favorites email to friend print save as pdf

Related Stories

2009 H1N1 vaccine protects against 1918 influenza virus

Jun 15, 2010

Researchers at Mount Sinai School of Medicine have determined people who were vaccinated against the 2009 H1N1 influenza virus may also be protected against the lethal 1918 Spanish influenza virus, which killed more than ...

NIH experts describe influenza vaccines of the future

Nov 17, 2010

In a review article appearing in the New England Journal of Medicine, scientists at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, examine research under way to ...

H1N1 influenza hits older children

May 04, 2010

Children hospitalized with pandemic H1N1 influenza in 2009 were older and more likely to have underlying medical conditions than children hospitalized with seasonal influenza during prior flu seasons, according to a study ...

Recommended for you

Guidelines presented for diagnosing focal liver lesions

11 hours ago

(HealthDay)—Focal liver lesions (FLLs) are mostly benign, and can be diagnosed based on knowledge of their presentation, associated clinical and laboratory features, and natural history, according to clinical ...

Factors tied to neck, back pain improvement identified

16 hours ago

(HealthDay)—Observational registry-based research can inform patients and physicians about prognosis for subacute or chronic neck or low back pain, according to a study published in the Aug. 1 issue of ...

User comments : 0