About the study
Sickle cell anaemia (SCA) is a common hereditary haemoglobin disorder in Africa. World wide
it is estimated that about 300,000 newborns are born every year. Of which 75% of them live in
Sub-saharan Africa (SSA). In Uganda, about 15,000 babies are born with sickle cell disease
In Uganda, the stroke prevalence was found to be 6.2% in children admitted to the National
referral hospital in Kampala. Notable between 21 to 30% of these children presented with
co-morbidities such as anaemia, bacteraemia and painfull crisis. Stroke in SCA is mediated by
several mechanism such as cellular adhesions, inflammatory markers, hemolysis associated
oxidative stress and hemostatic activation. Stroke in SCA is primarily a large vessel stroke
and the mechanisim state above lead to a narrowing of the lumen of the cerebral arteries
Arterial ischaemic stroke which occurs frequently in children with SCA has been associated
with bacterial infections. Recent studies have shown that minor infections such as flu like
infections can play a critical role in the trigger of stroke in children.
Our hypothesis is that viral flu infections is a key trigger for the risk of stroke in
children with SCA. Our objective is to prevent the occurrence of flu illnesses in children
with SCA thereby reducing the risk for stroke in our population of children with SCA.
Methods: A randomized controlled double blinded study Study site: The study will be conducted
at the Sickle Cell Clinic (SCC), Mulago Hospital. Inclusion criteria: will be ;age between 2
years and 12 years;All children whose parents will have consented and those above 7years will
have to assent. Exclusion criteria: all children with previous strokes; children who have
acute illness and are not clinically stable; any child with previous documented adverse event
following immunization (AEFI).
Sample Size: Using Open EPI calculator for cohort studies we calculated a total sample size
of 136 participant to achieve our objective. Using a 95% confidence interval, power of 80%
and an unexposed outcome of 25% (4) using a ratio of 1:1. Each arm will have 68 participants.
With anticipated 10% loss to follow up a total sample size of 150 with each arm having 75
Study utility: Globally, stroke triggers have been recently identified independent of the
existing risk factors such as high cerebral velocity speeds on TCDs. Flues like illnesses
have been reported to be stroke triggers in children with arterial ischaemic strokes
worldwide.This study may influence the role of influenza vaccination in the prevention of
stroke triggers in children with sickle cell anaemia. It will also add to the existing
modalities which have helped to reduce the incidence of stroke amongst this high risk group
of children with