“Nigeria on alert: Diphtheria outbreaks require urgent action” - A critical look at the current situation and potential solutions

Dear Editor,

Diphtheria is a bacterial infection caused by Corynebacterium diphtheriae, which is transmitted through close contact with infected individuals through respiratory secretions like coughing, sneezing, or talking. The bacteria release a toxin that can harm the organs, potentially leading to severe consequences or death. The disease primarily affects the nose, throat, and airways, causing breathing difficulties, fever, and the formation of a thick coating in the throat [1]. In Nigeria, diphtheria has been a long-standing concern for public health, much like in many other countries around the world. Nigeria has a record of repeated diphtheria outbreaks in the past. One of the most significant instances was reported to have taken place from February to November 2011 in the village of Kimba and the settlements surrounding it in Borno State, located in the northeast region of Nigeria. A total of 98 cases were found, with 64.3% of them were children under the age of 10 and none had received any prior vaccination and treatment against diphtheria. The overall case fatality rate (CFR) was 21.4 [2].

Recently the National Centre for Disease Control (NCDC) in Nigeria was informed of suspected diphtheria outbreaks in Kano and Lagos states on December 1st, 2022. As of third week of 2023, a total of 253 suspected cases of diphtheria have been reported across multiple states in Nigeria, including Kano (169 cases), Yobe (78 cases), Lagos (5 cases), and Osun (1 case). Out of them 111 (42.1%) were confirmed through either laboratory testing or clinical evaluation, 40 cases (15.3%) are still undergoing classification, and 84 (33.2%) are unknown. The majority (91.9%) of confirmed cases were found in children aged 2-14 years. Only a small percentage (10.8%) of confirmed cases were fully vaccinated with a diphtheria toxin-containing vaccine whereas majority of them were either unknown of their vaccination status or not vaccinated. The overall case fatality rate reported was about 19.8% [3].

The persistence of diphtheria in Nigeria has been linked to various factors, including low vaccine coverage, insufficient vaccine storage and transportation. Low accessibility to healthcare facilities, especially in rural regions, exacerbates the issue, resulting in delayed diagnosis and treatment. Furthermore, inadequate disease surveillance, laboratory surveillance and response systems, marked by a lack of resources, personnel, and cooperation between government agencies, impedes the effective detection and response to diphtheria outbreaks.(see Fig. 1)

Fig. 1.

Incidence of confirmed cases (per million population) in Kano state/LGA [3].

Health facilities in Nigeria are divided into three different tiers: primary (85.2%), secondary (14.4%) and tertiary (0.4%). Currently, there are 39,180 operational hospitals and clinics in the country. Unfortunately, only 43% of Nigerian citizens have access to quality primary healthcare services [4]. The issues in controlling diphtheria in Nigeria are mainly rooted in reduced vaccine coverage and limited access to healthcare facilities. According to National Immunization Coverage Survey (NICS) approximately 3.1 million (14%) children have zero or missed doses of vaccines. Moreover, 40% of these children did not receive any vaccines from the health system, while 49% received only the first of PENTA vaccine and only 33% were given all three doses of PENTA valent vaccine [5].

A major factor that has led to reduced coverage of vaccine is due to the lack of appropriate healthcare infrastructure in rural areas along with-it poverty and low educational levels may also lead to low vaccination rates. Moreover, limited access to healthcare and an absence of trained healthcare professionals impedes the effective treatment of diphtheria and decrease chances of early detection and treatment. To address these issues, concerted efforts are needed to increase vaccination coverage, improving access to healthcare facilities, strengthening surveillance systems, raising community awareness, and improving access to clean water and proper sanitation practices.

Strategy of contact tracing and early identification of individuals with symptoms needs to be adopted. This includes giving household contacts prophylactic antibiotics and vaccinations, as well as administering a dose of Td vaccine to accompanying contacts when they seek medical care. Further measures to monitor the situation include conducting widespread field surveillance, enhancing laboratory surveillance, and continuing chemoprophylaxis for adults living with diphtheria patients. Additionally, the government can launch campaigns to raise awareness about the importance of vaccination and encourage parents to have their children vaccinated. Improving access to healthcare facilities, especially in rural and remote areas, is essential for controlling the spread of diphtheria.

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