Human medicines European public assessment report (EPAR): Pandemic influenza vaccine H5N1 AstraZeneca (previously Pandemic influenza vaccine H5N1 Medimmune), pandemic influenza vaccine (H5N1) (live attenuated, nasal), Date of authorisation: 20/05/2016,…

Because a new pandemic live attenuated vaccine cannot be tested in children, the benefit of this vaccine in children was predicted from studies in adults and from studies of similar live attenuated flu vaccines in children.

Three main studies involving 107 adults found that Pandemic influenza vaccine H5N1 AstraZeneca was able to prepare the immune system to defend itself against the H5N1 virus strain in individuals who had never come into contact with it.

Antibodies against this type of vaccine are not easy to measure. However, a second vaccine that acts in a different way is able to make antibodies that can be measured easily. In those who received the second vaccine 3 weeks to 5 years after vaccination with Pandemic influenza vaccine H5N1 AstraZeneca, antibodies increased 4-fold in 73% (8 out of 11) of the individuals compared with 10% of the individuals who had not been previously vaccinated with Pandemic influenza vaccine H5N1 AstraZeneca. This showed that antibodies against Pandemic influenza vaccine H5N1 AstraZeneca increased substantially when vaccinated adults came into contact with the virus again. In addition, there is evidence indicating that the vaccine can protect against different strains of H5N1 virus. The results were similar to those from three other studies involving 170 adults given pandemic preparedness vaccines containing similar types of bird flu virus, such as H7N9 and H7N7, instead of H5N1.

In addition, the company presented extensive supportive data from large studies and from clinical practice on how well other similar pandemic and seasonal live attenuated influenza A vaccines work in children.

Further studies on the effects on the vaccine in children will need to be provided once the the flu strain causing the pandemic is included in the vaccine.