Seasonal Influenza Vaccine Effectiveness Study in Kenya

• Laboratory-confirmed influenza infection [ Time Frame: June 2010-March 2013 (3 yrs) ] [ Designated as safety issue: No ]
  Look at the number of vaccinated children who develop laboratory-confirmed influenza infection compared to a matched unvaccinated group of children.
  
  

• Medically attended Influenza Like Illness(ILI) and Severe Acute Respiratory Illness (SARI) [ Time Frame: June 2011-March 2013 (2 yrs) ] [ Designated as safety issue: No ]
  Look at the number of medically attended ILI and SARI in the unvaccinated group and compare to the vaccinated goup
  
  
• Community-reported ILI SARI [ Time Frame: June 2011- March 2013 (2 yrs) ] [ Designated as safety issue: No ]
  Look at the number of Community-reported ILI and SARI in the unvaccinated group and compare to the number in the vaccinated group
  
  
• Laboratory-confirmed influenza, medically attended ILI and SARI, and community-reported ILI and SARI in non-immunized household members [ Time Frame: June 2011-March 2013 (2 yrs) ] [ Designated as safety issue: No ]
  Look at the number of Laboratory-confirmed influenza, medically attended ILI and SARI, and community-reported ILI and SARI in non-immunized household members in both households that have a vaccinated child versus households that didn't have a vaccinated child
  
  

Vaccine will be donated by Sanofi Pasteur in a quantity large enough to vaccinate the eligible population. Vaccine will be made available to infants from 6 months of age through children up to 10 years old. This includes an age group that is at high risk for severe outcomes (<5 years) and an age group (school-age children, 5-10) that is considered most likely to spread the infection.

Ascertainment of Influenza Illness:

Primary Outcome Measure

• Laboratory-confirmed influenza infection

Secondary outcome measures

• Medically attended ILI, SARI
• Community-reported ILI SARI
• Laboratory-confirmed influenza, medically attended ILI and SARI, and community-reported ILI and SARI in non-immunized household members

In Lwak and Kibera, field workers visit households weekly and encourage residents to go to the free clinic if they have respiratory symptoms. Currently, from KEMRI/CDC surveillance data, in Kibera, approximately 57 % of people in the catchment area seek medical care for ILI (Range: 62% children - 52% adults) and of those people who seek care, 72% seek care at Tabitha clinic. In Lwak, approximately 77% of people in the catchment area seek medical care for ILI (Range: 75% children - 80% adults) and of those people who seek care, 34% seek care at Lwak clinic.

The surveillance for ILI and SARI will continue as usual, with weekly field worker (also called community interviewer) household visits, clinic-based surveillance for ILI and SARI at Tabitha clinic and Lwak clinic, and sampling of all patients who meet the case definition for ILI and SARI