Risk assessment of the 2015–2016 influenza season confirms that A(H1N1) is circulating as a seasonal virus but is included in the vaccine

WHO/Europe today released a risk assessment of the 2015–2016 influenza season in the WHO European Region, spanning week 40/2015 to week 4/2016. The early part of the 2015–2016 influenza season was marked by a very high proportion of cases due to influenza A(H1N1)pdm09 virus in most of the Region and an earlier increase in the number of severe cases in some eastern European countries than in previous seasons. As influenza A(H1N1)pdm09 is widely known as the cause of the 2009 pandemic, its identification in cases in the 2015–206 season might alarm the public. It is extremely important to communicate to the public that A(H1N1)pdm09 is now circulating as a seasonal influenza virus and that it is included in this season's flu vaccine.

Thus far, there is no evidence that this predominant flu virus – or the other circulating influenza A(H3N2) or influenza B viruses – have changed antigenically from those in the vaccine virus. There is also no evidence of reduced susceptibility to the antiviral drugs oseltamivir and zanamivir.

The WHO risk assessment includes a number of recommendations.

  • All Member States are encouraged to conduct influenza surveillance, provide timely alerts of unusual situations, share the resulting information for publication in the Flu News Europe bulletin and strengthen existing surveillance systems.
  • Member States should raise awareness among health care personnel that, because of the high proportion of cases due to circulating influenza A(H1N1)pdm09, severe disease in adults might occur more frequently this season.
  • Countries should provide their populations with information about the current influenza season and advice on effective public health measures to prevent influenza transmission, such as hand-washing, cough etiquette and staying at home if feeling ill. Although influenza is usually mild and most people recover quickly, it is important to emphasize that people who develop any severe respiratory symptoms that do not improve within 72 hours of onset should consult their physicians.
  • Authorities in countries with vulnerable populations and people displaced by crises should raise awareness among these groups, as they may have poorer access to health care. Health care workers should also be made aware of the risks of these vulnerable groups.
  • WHO recommends that health care workers and people who are most at risk for serious complications from influenza infection be vaccinated every year. Priority groups for vaccination include: pregnant women, individuals > 6 months of age with certain chronic diseases, elderly people, residents of institutions for older persons and the disabled, children aged 6–59 months and health care workers.

Read the full assessment and recommendations via the link below.