Annals of Tropical Medicine and Public Health

EDITORIAL COMMENTARY
Year
: 2013  |  Volume : 6  |  Issue : 1  |  Page : 1--2

Commentary on: Predicting changing measles epidemiology in an urban West African population


Tanmay Mahapatra 
 Department of Epidemiology, School of Public Health, University of California, Los Angeles, USA

Correspondence Address:
Tanmay Mahapatra
8 Dr. Ashutosh Sastri Road, Kolkata, West Bengal
USA




How to cite this article:
Mahapatra T. Commentary on: Predicting changing measles epidemiology in an urban West African population.Ann Trop Med Public Health 2013;6:1-2


How to cite this URL:
Mahapatra T. Commentary on: Predicting changing measles epidemiology in an urban West African population. Ann Trop Med Public Health [serial online] 2013 [cited 2020 Aug 6 ];6:1-2
Available from: http://www.atmph.org/text.asp?2013/6/1/1/115164


Full Text

Measles is considered to be one of the leading causes of vaccine preventable deaths among young children in developing countries. [1],[2] It is estimated by World Health Organization (WHO) and United Nation's Children Fund (UNICEF), nearly 77% of measles death occurred in South East Asia. [2] According to WHO/UNICEF estimates, routine first dose of measles vaccine coverage among infants was less than 80% in African region and South East Asia during 2008 and approximately 2 million children aged less than 1 year missed their first dose of measles vaccine in Nigeria. [2] Although there is a substantial decline in measles related mortality through comprehensive strategies adopted by WHO and UNICEF, some countries in Africa still continue to face recurrent epidemics. [1] It is evident from prior studies that improper immunization is the primary reason of under five mortality in some countries in sub-Saharan Africa. [1],[2]

Measles remains one of the most contagious diseases known affecting children. It is quite unfortunate to know that despite of availability of a safe and effective vaccine against measles almost four decades back, young children are dying due to measles related complications like pneumonia, diarrhea, encephalitis, or ear infections etc. [3]

The present paper aimed to predict the changing measles epidemiology in an urban West African population, but mainly focused on preventive role of maternal antibodies during measles among Nigerian young infants before they reach optimal age for measles vaccine. A review article by Caceres et al. indicates that the prevalence of maternal antibody to measles virus across countries and various socio-economic strata is very diverse and complex. [4] This review also pointed out that placental transfer is the key determinant of prevalence of maternal antibody to measles virus and this placental transfer is found to be linked with gestational age, Human Immunodeficiency virus and malaria. [4]

Since the authors in this article reported a hospital based observational study where eligible subjects were recruited from Departments of Pediatrics and Immunology in a tertiary care center in Maiduguri, Nigeria, in my opinion, interpretation of study findings should be done with caution due to the following reasons. First, study subjects were not a representative sample of source population as people who visited this hospital came from different geographic areas. Secondly, infants who required care from this center might be sicker compared to those in general population. Thirdly, caregivers of infants seeking care from this hospital could be economically better off which might be potential source for selection bias.

Researchers have argued that prevalence of measles maternal antibody is determined mainly by three factors namely initial level of maternal antibody, placental transfer of maternal antibody, and rate of decay of maternal antibody after birth. In this paper, author correctly identified these determinants influencing measles maternal antibody and pointed out their inability to measure initial maternal antibody or obtaining maternal measles immunization profile as limitations to this study. I think prevalence of maternal measles antibody varies across different geographic areas and is influenced by the vaccination status of the concerned population.

I believe in order to identify the epidemiological characteristics of measles in any population of a defined geographic area; we need to conduct an extensive research using an appropriate study design. Analysis of national measles case-based surveillance data collected over 4 years in order to assess the epidemiological trend in Vietnam showed that spatial distribution of the disease changed with time and disease prevalence varied across strata of age and gender. [5] In another hospital based case control study by Mandomandoet al. for assessment of epidemiology of measles in Southern Mozambique, reported age and immunization coverage of first dose of measles vaccine among children aged less than 1 year as important predictors of measles in a population and also indicated that further research was necessary to explore the role of HIV co-infection in measles related morbidity and mortality among young children. [6] Moss in his paper indicated that children who were co-infected with HIV-1 virus had higher odds of dying from measles compared to HIV sero-negative counterparts. [7]

I strongly support that in order to capture dynamics of any viral disease like measles, we need to i) collect data over a long period through a comprehensive surveillance system, ii) carry out research on genetic diversity of viral genomes for better understanding of epidemiology and transmission of such pathogen, and iii) applying appropriate statistical methods for analysis which will be easy to interpret iv) further explore various socio-environmental determinants of measles v) conduct further research on characteristics of underlying population of interest like economic condition, routine immunization coverage and prevalence of HIV infection. [8]

References

1Grais RF, Dubray C, Gerstl S, Guthmann JP, Djibo A, Nargaye KD. Unacceptably high mortality related to Measles Epidemics in Niger, Nigeria, and Chad. Plos Med 2007;4:e16.
2Morbidity and Mortality Weekly Report. Vol. 58. No. 47. Available from: http://www.cdc.gov/mmwr/PDF/wk/mm5847.pdf. [Last cited in 2009].
3Complications of measles. Centers for Disease Control and Prevention. Available from: http://www.cdc.gov/measles/about/complications.html. [Last cited in 2009].
4Caceres VM, Strebel PM, Sutter RW. Factors determining prevalence of maternal antibody to measles virus throughout infancy: A review. Clin Infect Dis 2000;31:110-9.
5Nmor JC, Thanh HT, Goto K. Recurring measles epidemic in vietnam 2005-2009: Implication for strengthened control strategies. Int J Biol Sci 2011;7:138-46.
6Mandomando I, Naniche D, Pasetti MF, Cuberos L, Sanz S, Valles X, et al. Assessment of the epidemiology and burden of Measles in Southern Mozambique. Am J Trop Med Hyg 2011;85:146-51.
7Moss WJ, Fisher C, Scott S, Monze M, Ryon JJ, Quinn TC, et al. HIV type I infection is a risk factor for mortality in hospitalized Zambian children with measles. Clin Infect Dis 2008;46:523-7.
8Pybus OG, Rambaut A. Evolutionary analysis of the dynamics of viral infectious disease. Nat Rev Genet 2009;10:540-50.