Indian Journal of Health Sciences and Biomedical Research KLEU

MINI REVIEW ARTICLE
Year
: 2021  |  Volume : 14  |  Issue : 1  |  Page : 31--37

Burden, epidemiological pattern, and surveillance gap of rubella in Nigeria: A call for routine vaccination policy


Kabir Adekunle Durowade1, Omotosho Ibrahim Musa2, Maryam Abimbola Jimoh3, Adekunle Ganiyu Salaudeen2, Oladimeji Akeem Bolarinwa2, Omowunmi Qubrat Bakare4, Lukman Omotayo Omokanye5,  
1 Department of Community Medicine, Afe Babalola University, Ado-Ekiti; Department of Community Medicine, Federal Teaching Hospital, Ido-Ekit, Nigeria
2 Department of Epidemiology and Community Health, University of Ilorin and University of Ilorin Teaching Hospital, Ilorin, Nigeria
3 Department of Immunizations, Vaccines and Emergencies/Expanded Program on Immunization, World Health Organization, Kwara State Field Office, Ilorin, Nigeria
4 Department of Community Health and Primary HealthCare, Lagos State University College of Medicine, Ikeja, Lagos State, Nigeria
5 Department of Obstetrics/Gynaecology, University of Ilorin and University of Ilorin Teaching Hospital, Ilorin, Nigeria

Correspondence Address:
Dr. Kabir Adekunle Durowade
Department of Community Medicine, Afe Babalola University, Ado-Ekiti (ABUAD)
Nigeria

Abstract

Rubella is an epidemic-prone disease with endemic transmission in Nigeria. It is a vaccine-preventable disease caused by the rubella virus whose devastating teratogenic effect makes it a disease of major public health importance when it occurs in pregnancy leading to congenital rubella syndrome (CRS) in infants. This article seeks to do a review of the burden, epidemiology, and examine the rubella surveillance gap in Nigeria. This is a review of literatures and the use of available World Health Organization secondary surveillance data to establish the burden, epidemiological pattern, and surveillance gap of rubella in Nigeria. Data were analyzed and presented with appropriate tables and charts. Epidemiologically, rubella occurs worldwide with seasonal variation. Available data from two geo-political zones (North-central and Southwest) of Nigeria showed that the peak incidence of rubella occur in the first 4 months of the year with most of the cases occurring in those <15 years and cuts across the rural and urban areas. Rubella and CRS are neglected diseases with no distinct surveillance system in place, no national incidence figure and no vaccination policy. The surveillance of rubella is integrated with that of measles with a noticeable poor case detection as only measles-negative blood samples are tested for rubella not minding the possibility of measles-rubella co-infection. With no national incidence figure and the gap in surveillance, rubella is under-reported in Nigeria. There is a need for a bridge of the surveillance gap and the government should have routine vaccination policy on rubella introduced in Nigeria.



How to cite this article:
Durowade KA, Musa OI, Jimoh MA, Salaudeen AG, Bolarinwa OA, Bakare OQ, Omokanye LO. Burden, epidemiological pattern, and surveillance gap of rubella in Nigeria: A call for routine vaccination policy.Indian J Health Sci Biomed Res 2021;14:31-37


How to cite this URL:
Durowade KA, Musa OI, Jimoh MA, Salaudeen AG, Bolarinwa OA, Bakare OQ, Omokanye LO. Burden, epidemiological pattern, and surveillance gap of rubella in Nigeria: A call for routine vaccination policy. Indian J Health Sci Biomed Res [serial online] 2021 [cited 2021 Feb 27 ];14:31-37
Available from: https://www.ijournalhs.org/text.asp?2021/14/1/31/308968


Full Text



 Introduction



Rubella (also called German measles) is a vaccine-preventable viral disease of public health significance caused by the rubella virus (RV). It is a mild febrile rash illness in children and adults; and these two symptoms of fever and maculopapular rash are the common presentation of the disease.[1] The rubella rash occurs in 50%–80% of rubella-infected persons and is sometimes wrongly diagnosed as measles or scarlet fever.[1] Other symptoms include posterior auricular and sub-occipital lymphadenopathy, headache, myalgia, among others. Rubella infection early in pregnancy, particularly during the first trimester can severely affect the fetus resulting in miscarriage, fetal death, or a baby born with a combination of disabling conditions collectively called congenital rubella syndrome (CRS).[2],[3]

The CRS affects virtually all organs causing disease conditions which include heart disease, blindness, and deafness.[2],[3] The common birth defects are ocular (cataracts, retinitis, microphthalmia, and glaucoma), hearing impairment, heart defects (pulmonary stenosis and persistent ductus arteriosus), microcephaly, developmental delay, mental retardation, and damage to the liver and spleen. Other adverse effects of rubella infection in early pregnancy or just before conception include fetal resorption, spontaneous abortion, and intrauterine foetal death. If acquired in pregnancy, especially in the first trimester, serious consequences may ensue in up to 90% of cases resulting into CRS.[3],[4] The major public health concern posed by rubella is its teratogenicity; and this devastating teratogenic effect makes rubella a disease of major public health importance when it occurs in pregnancy.[5],[6] The public health burden associated with rubella is connected to the risk of infection in pregnancy, which, in turn, may lead to CRS in infants.

The World Health Organization (WHO) recommends that countries, such as Nigeria, with no rubella vaccination programs in place should assess the burden of rubella and CRS through effective surveillance. Surveillance data are critical to measles and rubella control and eradication efforts. With adequate surveillance, the burden of disease and mortality can be established, and hence, play an important role in advocacy and prioritization of activities geared targeted at rubella. Indeed, surveillance measures disease incidence, the best outcome indicator of disease control and eradication programmes.

Therefore, this paper aimed to: (1) review the burden of rubella in Nigeria, (2) assess the epidemiology of rubella in Nigeria, (3) present the gap in the surveillance system of rubella in Nigeria, and (4) advance reasons on the need for a paradigm focus on rubella vaccination in Nigeria.

 Methodology



This is essentially a review of literatures involving internet search. Scholarly and relevant research materials were retrieved, findings sieved and triangulated. In all, a total of 35 reference materials were finally used for this review paper. Relevant secondary data on rubella surveillance obtained for the WHO African region (available from the WHOs website) on rubella surveillance were also analyzed and presented in this review. Furthermore, secondary surveillance data, for the years under review, for the North-central geopolitical zone in Nigeria as collated by the relevant WHO office, were extracted, analyzed, and presented in this review. Data quality is ensured through a multilevel validation as surveillance data used in this review are collected/collated and validated at four different levels (Local, State, Zonal and National) in Nigeria.

 Burden of Rubella in Nigeria



Rubella seroprevalence in the African region range from 71% to 91% and varied by age group (from 84% to 94% among women of reproductive age (Suleiman et al., 2016). In a case-based surveillance of rubella in Cameroon, a total of 9907 serum samples were received in the laboratory from 2008 to 2014, 75.59% measles-negative samples were tested for rubella; 699 (9.3%) were positive for rubella immunoglobulin M (IgM) antibodies.[7] In another study by Tamirat et al.[8] in Hossawa, Southern Ethiopia, the seroprevalence of anti-rubella IgM and immunoglobulin G (IgG) antibodies was found to be 2.1% and 86.3%, respectively. In a study conducted by Mirambo et al.[9] among Tanzanian children in the prevaccination era, of the 723 enrolled participants, 368 (50.8%) and 94 (13%) were positive for specific IgG and IgM rubella antibodies, respectively. In South Africa, the 2017 National Institute of Communicable Disease reported that, out of the total specimens for measles surveillance, a total of 36.5% samples tested for rubella IgM from all the nine provinces.[10]

Just like many other African countries, rubella is endemic in Nigeria. However, rubella and CRS are neglected diseases with no surveillance system in place and no national incidence figure.[11] However, some studies have been done in Nigeria to establish the seroprevalence of rubella. Studies among the women of child-bearing age in Nigeria put the seroprevalence at 66.6% in Imo, 77% in Lagos and 93.5% in Oyo.[12] In Ilorin, Nigeria, studies have obtained a seroprevalence of 16.3% of antenatal RV infection among 92 pregnant; and 87% (IgG seropositivity) and 1.5% (IgM seropositivity) among women of child-bearing age.[13],[14] In another study in Ilorin, Nigeria by Suleiman et al.[12] only 23 (8.1%) were seropositive for Rubella-specific IgM antibody. Furthermore, in the Ilorin study, all the 23 participants with rubella-specific IgM antibodies also had rubella-specific IgG antibodies. In Osogbo, South-west Nigeria, 175 (87.5%) were positive and more than three quarters, 85%, had a positive result in the age group of 3034 years (P = 0.716).[15] Most cases of rubella and CRS occur in low- and middle-income countries, and despite being an epidemic-prone disease, rubella cases are mostly under-reported, especially in developing countries of the world. Furthermore, substantial commitment to rubella control has not been demonstrated in developing countries such as Nigeria.[16]

 Epidemiology of Rubella in Nigeria



Rubella occurs worldwide with a seasonal variation except in countries where the disease has been eliminated. In countries with temperate climates, the disease tends to peak during the spring and late winter with epidemics every 5–9 years. The extent and periodicity of the rubella epidemics are highly variable in both developed and developing countries. The RV is transmitted by airborne droplets when infected people sneeze or cough. Humans are the only known host. In 1969, in the prevaccination era, widespread outbreaks usually occurred every 6–9 years in the United States and 3–5 years in Europe, mostly affecting children in the 5–9-year-old age group. Since the introduction of vaccine, occurrences have become rare in those countries with high uptake rates.[16]

In Africa, RV is circulating widely and children are primarily infected. Analysis of surveillance data showed that by 15 years of age, most children have developed immunity from natural infection. Of the reported cases of rubella, 5% have been found among the women of reproductive age group.[16] A number of previous studies[17],[18],[19],[20] on rubella transmission in the African region among women of child-bearing age have documented the widespread circulation of RV.

While there are no national data on the prevalence or incidence of rubella as earlier stated, studies have shown that the prevalence of rubella varies across the different geo-political zones in Nigeria and with seasonal peak. However, point prevalence from serological surveys which estimated susceptibility to rubella infection among children suggested that, by 15 years of age, most children have developed immunity against natural infection.[21],[22] Regardless of the immunity, recurrent exposure to already infected people increases the seropositivity of the children most, especially in crowded environments such as schools, playgrounds, and during convergence for social function.[22]

As shown in [Figure 1], available secondary data showed that the seasonal peak of rubella in Nigeria is seen in the first 4 (January–April) months of the year. Therefore, the peak incidence occurs during the dry season in Nigeria. In the 4 years depicted in the graph, the highest number of reported cases in Nigeria was seen in February 2016. While the peak is seen in the first 4 months of the year, there is a plateau in the number of reported cases from September to October. In between these two periods, the pattern in the number of reported cases assume a waxing and waning pattern with peaks and troughs. A number of studies have also been in Nigeria on the epidemiology of rubella in Nigeria.{Figure 1}

A retrospective study conducted in Kebbi State, North-west Nigeria, showed that rubella infection was found to be common among the under five children with a peak incidence during the hot season (between February and April).[23] In South-west Nigeria, Fatiregun et al.[24] analyzed the measles-cased surveillance for the period 2007–2012 which revealed that rubella infections occurred widely in the geopolitical zone and primarily affect young children. During the period under consideration, the cases of rubella were reported from all the six states of the South-west zone. The age distribution of cases showed a range from 3 months to 56 years with a median of 4 years. However, majority of the cases were individuals <15 years of age and 40.9% were females. The triannual peak shown in [Figure 2] for Q1 (January–April) was also demonstrated by Fatiregun et al.[24] in South-west Nigeria as the data showed the highest seasonal variation for tri-annual period 1/Quarter 1 [Figure 2]. In terms of geographical distribution, Yahaya et al.[11] also showed, in another review of the prevalence of rubella between 1977 and 2015, that the distribution of rubella infection (IgM and IgG) in Nigeria based on age groups, gender, and location did not show consistent trend of infection among rural and urban settings. However, such as other studies, females were more affected than the males.[24]{Figure 2}

Furthermore, available surveillance data from the North Central geopolitical zone for the year 2018 up till the 11th epidemiologic week of 2019 showed that rubella is common among age groups <15 years of age with more IgM seropositivity than those who are 15 years and above. However, it affected both males and females almost equally. In addition, the rural areas of the zone had more positive cases compared with the urban areas; and of the three tri-annual periods, the first one, Q1 (January–April) had the highest number of cases, as shown in [Table 1]. Also, Plateau has the highest number of rubella cases [Figure 3] and the highest percentage positivity [Table 2] in the North central zone of Nigeria for the period under consideration.{Figure 3}{Table 1}{Table 2}

 Gaps in Surveillance of Rubella in Nigeria



Surveillance has long been recognized as a veritable tool for effective infection prevention and control. According to the WHO,[25] public health surveillance is the continuous, systematic collection, analysis, and interpretation of health-related data needed for planning, implementation, and evaluation of public health practice. It may be used to serve as an early warning system for impending public health emergencies; chronicle the impact of an intervention, or track progress toward specific goals; and monitor and clarify the epidemiology of health problems, to allow priorities to be put in place and to inform public health policy and strategies.[26],[27],[28],[29] Effective disease surveillance is, as earlier stated, essential for an effective communicable disease control and indeed, functional national communicable disease surveillance is essential for action on priority communicable diseases such as rubella.[25],[26]

Surveillance of rubella becomes a priority when a country sets elimination targets. This usually occurs at the time the country establishes measles elimination targets. Hence, combined measles/rubella rash illness surveillance is a key component of measles/rubella elimination. In Nigeria, rubella surveillance is integrated with measles surveillance as the WHO measles case definition also captures rubella cases.[26],[28],[29] The confirmation of rubella cases is very similar to that of measles, hence, the integration of the surveillance system.[29] For field work in rubella surveillance, there are case definitions and laboratory procedures that are operationalized on the field.

In Nigeria, just like in many countries in the WHO, AFRO regions with no specific rubella surveillance system, surveillance data are collected through the national measles surveillance systems that use a standardized WHO regional case definition of fever and generalized maculopapular rash, and at least 1 of these symptoms: cough, coryza (runny nose), or conjunctivitis. Therefore, the surveillance for rubella is subsumed under/merged with that of measles in Nigeria. Every suspected case is captured on a case investigation form and information on age, sex, vaccination status, and residence are taken.[30] Blood specimens are collected from five suspect cases when there is suspicion of an outbreak. However, there is no dual testing of each blood sample for both measles and rubella as only specimens that test negative or indeterminate for measles-specific IgM antibody that are tested for the presence of rubella-specific IgM antibody using a standard enzyme-linked immunosorbent assay. A confirmed rubella case is defined as an IgM-negative measles cases that is IgM positive for rubella as defined by Luce et al.[30] It is noteworthy to state that except measles-positive samples are tested for rubella, it is not possible to establish measles-rubella co-infection with the present surveillance system causing underreporting and missed cases. Hence, with the present combined measles-rubella surveillance system in Nigeria, it will be impossible to detect dual infection unless each sample collected is tested for both measles and rubella. However, co-infection with measles and rubella has been demonstrated in an outbreak of suspected measles in Chitradurga district, Karnataka, India, where serological results showed that out of 21 serum samples, 9 (39.1%) were positive for measles IgM antibodies, 7 (30.4%) were positive for rubella IgM antibodies, and 5 (23.8%) serum samples showed dual infection with measles and rubella mostly in the children 1–10 years.[31]

 Need for a Policy on Rubella Routine Vaccination in Nigeria



There is no immunization policy on rubella vaccination in Nigeria.[32] It is over 50 years since the syndrome of congenital abnormalities following maternal rubella infection was first recognized; despite this, rubella immunization rates are not optimal and infections during pregnancy still occur.[6] Many countries, including Nigeria, have not incorporated rubella vaccine in their national routine immunization program despite the burden associated with its devastating sequel. Therefore, 5%–25% of women of child-bearing age lack Rubella IgG antibodies and are susceptible to primary infection.[6] As stated by Mirambo et al.,[9] the WHO advocates the assessment of the burden of rubella and CRS by seroepidemiological surveys and surveillance programs in all countries without vaccination programs. Despite the availability of safe and effective vaccines, and the elimination of the RV in many developed countries, substantial commitment to rubella control has not been demonstrated in developing countries such as Nigeria.[16],[33]

As most cases of rubella and CRS occur in low- and middle-income countries; and despite being an epidemic-prone disease, rubella cases are mostly under-reported, especially in developing countries of the world.[34] This can be ascribed to the low attention and inadequate drive/commitment and weak funding toward elimination strategies, particularly routine rubella vaccination.[23] In spite of the burden of rubella and devastating sequel, rubella is still among the small number of viral diseases considered to be potentially eradicable according to.[16] Rubella can be eliminated in countries that have introduced routine rubella vaccination for children and achieved high coverage in the population.[16] However, countries that introduce rubella vaccine and achieve suboptimal vaccination and surveillance coverage may be at risk for a paradoxical increase in susceptibility among older age groups, potentially leading to acquisition of RV infections among women of child-bearing age and to an increase in CRS cases. The paradoxical increase among the older age groups is as a result of the immunity gap that will occur among the older age groups once the routine rubella vaccination focuses only the infants with sub-optimal coverage; and to prevent this, the WHO advocates an initial mass immunization campaign before introduction of the vaccine into the National routine immunization schedule.[16]

In terms of cost, Babigumira et al.[32] affirmed that rubella vaccination programmes are economically justifiable; and economic analysis for rubella and CRS control suggest that incorporation of rubella-containing vaccine (RCV) into national childhood immunization schedules is both cost-beneficial and cost-effective. While there is a dearth of studies on the cost of treatment CRS in low-income countries, estimates suggest a wide range for the life-time cost of treating a single CRS case from US$4200 (inflation-adjusted 2012), in a middle-income country such as Brazil, to over US$200 000 (inflation-adjusted 2012), in a high-income country such as the USA.[32] Despite this emphasis on the importance of rubella vaccination, coverage for rubella vaccine in the African continent, Nigeria in particular, is still abysmally low or nonexistent.[12],[15],[23],[33],[35] Therefore, to combat rubella and its associated sequel of CRS in Nigeria, there is a need for a paradigm focus on the urgent need to incorporate rubella vaccination into the National Immunization Schedule.

 Conclusion



Rubella is a mild febrile rash viral infection caused by the RV. It is an acute, contagious, generally mild infection that affects both children and adults including both sexes with attendant sequel of CRS if it occurs in pregnancy. Review of the findings of seroprevalence surveys done across the different parts of Nigeria demonstrates the burden and the endemic transmission of the disease. Epidemiologically, rubella occurs worldwide with a seasonal variation. Available data from two geo-political zones (North-central and Southwest) of Nigeria showed that the peak incidence of rubella occur in the first 4 months of the year with most of the cases occurring in those <15 years. Furthermore, the seasonal pattern in Nigeria showed a peak incidence occurring in the first quarter of the year. Despite the associated and devastating sequel, Nigeria and most countries in Africa does not have a distinct surveillance system for rubella as rubella case search is subsumed under that of measles causing high number of missed cases and under-reporting.

 Recommendations



A functional and effective surveillance for rubella, like that of measles, is essential for an effective control of the disease. There is need to have a separate surveillance system for rubella with adequate training of the primary healthcare workers on rubella case search; or in the alternative, rubella surveillance should be made more prominent as against being subsumed under the measles surveillance as it is currently being practiced. In other words, the introduction of either a distinct rubella case-based surveillance or having a joint measles-rubella case-based surveillance system combined, in order to amplify rubella search, are options that can be considered by Nigerian Government.

All efforts and machineries should be put in motion by Nigerian government to incorporate RCV in the routine immunization schedule for infants (at 9 months) and young children (aged 15 months–6 years) with regular vaccination campaigns for older children and adults in order to close the immunity gap. The government should anticipate and address demand and supply disequilibrium in the RCV logistic by putting policies in place to address demand, such as advance purchase commitments, strong vaccine forecasting, efficient procurement system and government stockpiles; and for supply arm, the government should encourage local production through basic vaccine research, liability protection for the manufacturers and fast-track approval for the new vaccine.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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