Clinical Epidemiology of Chickenpox in Iraq, 2007- 2011

Chickenpox (Varicella zoster) infection is an acute disease caused by varicella zoster virus (VZV). In
endemic areas, primary infection tends to occur at a younger age. The World Health Organization
(WHO) recommended that routine childhood varicella vaccination should be considered in countries
where the disease is a relatively important public health and socioeconomic problem, and where high
(85 to 90%) and sustained vaccine coverage can be achieved.
Aim: 1- To describe the epidemiology (occurrence, age, gender and season) of registered clinical
cases of chickenpox in Iraq from 2007-2011, 2- To determine the need for the use of chickenpox
vaccine in Iraq.
Methods: A retrospective descriptive analysis of surveillance data. Frequency and percentage were
used to describe the data. The occurrence per 100,000 of Iraqi population was calculated. Chi square
test was used.
Results: There was an obvious rise in the registration of clinical chickenpox cases from 21,798 case
in 2007 to 74, 195 case in 2011. This corresponds to an increase in the occurrence rate of clinical
chickenpox cases from 73.41/100,000 in 2007 to 222.61/100, 000 in 2011. There were possible
outbreaks in 2008 and 2011. The occurrence of chickenpox showed the same seasonal distribution
throughout the years 2007-2011, being highest in spring (April, May) season. The highest registered
number of chickenpox cases was in provinces of Ninawa, Baghdad/Russafa, Dihok, Baghdad/Karkh,
Al-Basrah and As-Sulaymaniyah. There was a sustained preponderance for the males over females
with nearly the same percentage over the years. Most of the cases occurred in those of age 5-14
years (65%), only 1% occur in those >45 years with statistical significance p=0.001.
Conclusions: There is a rising trend in the registration of clinical chickenpox cases. Most cases occur
in the age group of less than 15 years. Males are slightly higher than females. The highest
frequencies were reported in March, April and May. Most of the cases were registered in Baghdad,
Ninawa, Dihok and Al-Basrah.