Seasonal Influenza Vaccine Effectiveness Study in Kenya

Study Overview
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Brief Summary
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Influenza is an important cause of acute respiratory infections (ARI) worldwide. Seasonal influenza causes an estimated 250,000-500,000 deaths and 3-5 million severe illnesses each year (WHO, 2009), and pandemic 2009 H1N1 influenza has caused morbidity and mortality worldwide. In Kenya, influenza accounts for up to 50% of all ARI during the peak influenza season, based on Kenyan Ministry of Public Health and Sanitation and KEMRI/CDC surveillance data. Influenza vaccine has been shown to reduce influenza-associated ARIs in developed countries. However, little is know about the effectiveness of influenza vaccine in the developing world. In Kenya, a commercial trivalent injectable vaccine is licensed, but less than 30,000 doses are sold annually. The International Emerging Infections Program (IEIP) under KEMRI/CDC currently conducts population-based disease surveillance (PBDS) for severe acute respiratory illness (SARI) and influenza-like illness (ILI) in two sites in Kenya, Lwak (Nyanza province) and Kibera (Nairobi). The investigators propose to conduct a three-year influenza vaccine effectiveness study using the commercially available southern hemisphere seasonal vaccine for 2010, which includes the pandemic 2009 H1N1 component, and for 2011 and 2012. The study will evaluate the effectiveness of the vaccine in preventing laboratory-confirmed influenza, non-specific ARIs at the clinic and household level, and secondary influenza infection and secondary ARIs. Our study hypothesis is: Immunizing children with influenza vaccine will decrease influenza-associated acute respiratory infections among children and may reduce the number of non-specific acute respiratory infections in vaccinated children and their household contacts.

Detailed Description
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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

Official Title
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Seasonal Influenza Vaccine Effectiveness Study in the Kenyan Communities of Kibera and Lwak

Conditions
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Influenza, Influenza Like Illness, Severe Acute Respiratory Illness

Intervention / Treatment
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* Biological: Seasonal influenza vaccine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 6months -10 years Enrolled in the IEIP morbidity study Exclusion Criteria: Age less than 6 months or greater than or equal to 11 years Not enrolled in the IEIP morbidity study

Ages Eligible for Study
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Minimum Age: 6 Months
Maximum Age: 10 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Vaccinated group<br>Children between 6months- 10years of age who have received the influenza vaccine | Biological: Seasonal influenza vaccine<br>* annual recommended Southern Hemisphere vaccine<br>* Other names: Vaxigrip;|
| Unvaccinated group<br>Eligible children between 6months and 10years who didn't receive the influenza vaccine | Biological: Seasonal influenza vaccine<br>* annual recommended Southern Hemisphere vaccine<br>* Other names: Vaxigrip;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Laboratory-confirmed influenza infection | Look at the number of vaccinated children who develop laboratory-confirmed influenza infection compared to a matched unvaccinated group of children. | June 2010-March 2013 (3 yrs) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Medically attended Influenza Like Illness(ILI) and Severe Acute Respiratory Illness (SARI) | Look at the number of medically attended ILI and SARI in the unvaccinated group and compare to the vaccinated goup | June 2011-March 2013 (2 yrs) | 
| Community-reported ILI SARI | Look at the number of Community-reported ILI and SARI in the unvaccinated group and compare to the number in the vaccinated group | June 2011- March 2013 (2 yrs) | 
| Laboratory-confirmed influenza, medically attended ILI and SARI, and community-reported ILI and SARI in non-immunized household members | 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 | June 2011-March 2013 (2 yrs) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Influenza, Influenza vaccine, Influenza vaccine effectiveness study