| Effect of varicella vaccine introduction on chickenpox
incidence in Kingdom of Bahrain |
Afaf Mohammed1,2 
, Hasan Isa3,4
, Malak Hasan5
, Maram Hasan5
, Ali Moosa4
, Janan Radhi6
, Basma Al Saffar1,7
, Adel Al Sayyad8,9
|
1Public Health Consultant, Public Health Directorate, Ministry of Health, Manama, Bahrain
2Consultant Family Medicine & Public Health, Ministry of Health, Manama, Bahrain
3Associate Professor, Department of Pediatrics, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain
4Consultant, Department of Pediatrics, Salmaniya Medical Complex, Manama, Bahrain
5Intern doctor, Royal Medical Services, Riffa, Bahrain
6Clinical attachment, Department of Pediatrics, Salmaniya Medical Complex, Manama, Bahrain
7Medical student, Royal College of Surgeons in Ireland, Muharraq, Bahrain
8Consultant Family Medicine, Epidemiology & Public Health, Chief of Disease Control Section, Ministry of Health, Manama, Bahrain
9Consultant Family Medicine, Epidemiology & Public Health, Ministry of Health, Manama, Bahrain
10Associate Professor of Family and Community Medicine, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain |
Correspondence:
Hasan Isa, Email: halfaraj@hotmail.com
|
|
Received: 21 May 2026 • Revised: 2 August 2026 • Accepted: 10 August 2026 |
|
|
| Abstract |
Background
Chickenpox (varicella) is a highly contagious
and self-limiting disease in children. However, complications
and hospitalizations may occur. In Bahrain,
the varicella vaccine was introduced into the routine
childhood immunization schedule in May 2015. However,
published data describing the epidemiological patterns of
varicella postvaccine introduction are limited.
Purpose
This study aimed to estimate varicella vaccine
effectiveness (VE); investigate changes in varicella incidence
and seasonal variation; compare age groups, healthcare
utilization, and hospitalization; and identify predictors
of vaccine uptake.
Methods
This retrospective national study included all
clinically diagnosed varicella cases reported to the Public
Health Directorate in Bahrain in 2010–2024. Annual and
age-specific incidence rates and seasonal variations
were
calculated. Demographic characteristics, healthcare settings,
and hospitalizations were compared by vaccination
status. Varicella VE was estimated using a screening
method
.
Results
Of the 34,499 varicella surveillance records,
32,177 were confirmed as chickenpox cases (15,579 in 2010–
2013, 16,598 in 2014–2024). The annual incidence peaked at
251.8 per 100,000 in 2015 and declined to 28.5 per 100,000
by 2024 postvaccination (88.7% reduction). Seasonal peaks
were more evident between 2014 and 2019 but became less
pronounced thereafter. Most patients
were male (57.4%),
Bahraini nationals (69.1%), or unvaccinated (90.1%). The
most affected age groups were children aged 5–9 years
(36.1%) and 0–4 years (28.4%). More than 98% of the cases
were managed in primary healthcare settings. Only 12 of
the unvaccinated patients (0.1%) required hospitalization.
The calculated VE ranged from 97.7% to 100%. Compared
to children aged 0–4 years, all older age groups had significantly
lower odds of vaccination (P<0.001). Similarly,
non-Bahraini patients
had a lower odd than Bahraini patients
(odds ratio, 0.744; 95% confidence interval, 0.633–
0.875; P<0.001).
Conclusion
The introduction of routine childhood
varicella vaccination in Bahrain resulted in a substantial
decline in the incidence of varicella, particularly among
vaccine-eligible children. Severe diseases requiring hospitalization
are rare and occur only in unvaccinated individuals.
Age and nationality were independent predictors
of vaccine uptake. |
| Key Words:
Varicella, Chickenpox, Chickenpox vaccine,Incidence, Bahrain |
|
PDF Links
Download Citation
