Clinical epidemiology of chickenpox in Iraq from 2007-2011

Varicella zoster (chickenpox) infection is an acute common disease caused by the varicella zoster virus (VZV). Children are most susceptible to infection. In non-vaccinated populations, primary infection tends to occur at a younger age. In 1998, the World Health Organization (WHO) recommended that routine childhood varicella vaccination 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.

1- To determine the trend (occurrence, age and gender distribution, seasonal variation) of registered clinical cases of chickenpox in Iraq from 2007-2011. 2- To determine the need for the use of chicken pox vaccine in Iraq and putting a plan for its use accordingly.

Retrospective descriptive study.

Frequency of clinical cases shows an obvious rise in the registration of chickenpox cases from 21798 case in 2007 through 59681 in 2008 to 74195 in 2011 with possible outbreaks occurred in 2008 and 2011. Rate of occurrence of clinical chickenpox cases also shows an obvious rise in the occurrence that ranges from 73.41/100000 in 2007 to 222.61/100000 in 2011. The rate in 2008 and 2011 is suggestive of a possible outbreak. Although the total number of chickenpox varies from 2007-2011 but all have shown the same seasonal distribution, being highest in spring (April, May) season. The largest no. recorded was in 2011 (14000 cases in April and May). The lowest no. recorded was in 2007 (4000 cases in April and May).The highest registered number of chickenpox cases was in provinces of Ninawa, Baghdad/russafa, Dihok, Baghdad/karkh, Al-Basrah, As-Sulaymaniyah. Regarding gender distribution there was sustained preponderance for the males over females with nearly the same percentage over the years. Age distribution of the registered cases had shown that 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.

1- There is a rising trend in the registration of clinical chickenpox cases. 2- Most cases occur in the age group of less than 15 years. Males are a little bit higher than females. 3- The highest frequencies were reported in March, April, and May.4- Most of the cases were registered in Baghdad, Ninawa, Dihok and Al-Basrah.