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Dissemination Centre

Evidence at a glance on pandemic flu

The World Health Organisation defines a flu pandemic as occurring when a new flu virus emerges and spreads around the world and most people do not have immunity.

How did vaccines help in the pandemic?

  • Two new vaccines – tested during the last flu pandemic – both offered immunity to the H1N1 strain of flu.
  • An ‘adjuvanted’ vaccine (one that uses an additional ingredient as well as the virus) produced immunity in more people but resulted in more adverse reactions such as fever.
  • Overall the adjuvanted vaccine appeared the best option, though older people may need two doses to develop immunity.
  • The flu vaccine proved highly effective in preventing flu and associated complications such as pneumonia.

How does pandemic flu affect pregnant women and their babies?

  • Pregnant women who develop flu have a greater risk of complications such as premature delivery, especially if they smoke, have asthma, are overweight or obese.
  • Antiviral drugs given to pregnant women with flu reduced the severity of their illness.

What lessons were learned for future research in a pandemic?

  • The NIHR is ready to support vital research in the event of another flu pandemic. A portfolio of approved studies is ready and waiting to start, which will enable faster and more effective research if and when the time comes.

Questions for clinicians and members of the public

For clinicians:

  • Do we have a reliable system in place to ensure that pregnant women and children receive a seasonal flu vaccination?

For patients:

  • Am in a ‘high risk’ group for flu?
  • Do I know how to and when to get a seasonal flu vaccination?

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