Abstract
Saudi Arabia (SA) experienced two large invasive meningococcal disease (IMD) outbreaks during the 2000 and 2001 Hajj pilgrimages. In 2002, polysaccharide quadrivalent ACWY vaccines became mandatory for Mecca and Medina pilgrims/residents older than two years. This study aimed to analyse IMD surveillance data among citizens, residents and pilgrims in SA from 1995 to 2011, focusing on changes before and after the new vaccination policy. For all laboratory-confirmed IMD cases in the national surveillance database from 1995 to 2011, serogroup and age were retrieved. The cases' seasonal distribution as well as the case fatality ratios (CFR) were obtained. For Saudi citizens/residents and Hajj pilgrims, annual rates were calculated using mid-year population estimates. The Student's t-test was used to compare means between the pre-epidemic (1995-1999) and post-epidemic (2002-2011) periods, excluding outbreak years. From 1995 to 2011, laboratories notified 1,103 cases. Between the pre- and post-epidemic periods, mean annual IMD rates decreased from 0.20 (standard deviation (SD): 0.1) to 0.06 cases/100,000 (SD: 0.06; p=0.02), mean numbers of Hajj-related cases from 13 (SD: 9.3) to 2 cases/year (SD: 2.3; p=0.02) and the mean age from 31 (SD: 1.3) to 18 years (SD: 1.4; p<0.01). The CFR in Saudi citizens (10.4) was lower than among foreign pilgrims (28.9) and decreased from 19.3% (SD: 1.8) in the pre-epidemic to 11.4% (SD: 7.0; p=0.04) in the post-epidemic phase. The decrease of annual IMD rates, CFR and Hajj-related cases between the pre- and post- vaccine era suggests a possible positive effect of the mandatory ACWY vaccination for pilgrims/residents in Mecca and Medina. Regular surveillance with an annual data analysis is necessary to monitor trends and circulating serotypes and to implement appropriate public health measures to avoid new IMD epidemics during upcoming Hajj seasons.
Highlights
Invasive meningococcal disease (IMD) is caused by the gram-negative coccoid bacterium Neisseria meningitidis [1,2]
This study aims to describe the epidemiology of invasive meningococcal disease (IMD) in Saudi Arabia for the years 1995 to 2011, with a focus on changes in incidence and case fatality ratio (CFR) after the introduction of the polysaccharide quadrivalent ACWY vaccine in 2002, in order to evaluate the effect of this Hajj vaccination policy change
Our study indicates that the incidence of IMD decreased in Saudi Arabia (SA) following the introduction of the ACWY vaccine in 2002
Summary
Invasive meningococcal disease (IMD) is caused by the gram-negative coccoid bacterium Neisseria meningitidis [1,2]. Transmission via respiratory droplets can lead to bacterial meningitis and septicaemia in the persons who get infected. Six serogroups (A, B, C, W135, X and Y) differentiated by their polysaccharide capsule, account for the majority of IMD cases [3]. IMD primarily affects children below five years of age, causing an estimated 500,000 cases and 50,000 deaths annually worldwide [4]. Polysaccharide and conjugated vaccines are available for serogroups A, C, W135 and Y [5]. One vaccine for serogroup B has been licensed in Europe in January 2013 and other serogroup B vaccines have been used in New Zealand, Cuba and France to control epidemics [6]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
