Diphtheria, an acute bacterial disease caused by toxigenic strains of Corynebacterium diphtheriae and occasionally Corynebacterium ulcerans has been eradicated from most countries following consistent childhood vaccination campaigns decades ago using the using a diphtheria toxoid-containing vaccine.
The World Health Organisation, WHO, said cases of diphtheria declined from about 100,000 in 1980 to less than 10,000 in 2021.
But as a result of gaps in immunisation coverage, Nigeria is today battling with the outbreak of this forgotten disease which has claimed 62 lives and affected 21 States, according to the Nigeria Centre for Disease Control and Prevention, NCDC, situation report for Week 19, 2022 to Week 09, 2023. Excerpts:
When the first case of diphtheria was discovered, it sounded very strange to some Nigerians but as the day goes by, it was indeed added to the list of infectious diseases such as Lassa fever, COVID-19, Monkeypox, yellow fever among others plaguing Nigeria.
It is also no longer news that diphtheria was not something that is on health facilities' radar but since 2022, Nigeria has recorded over 1,064 suspected cases with 389 confirmed cases.
Further statistics obtained by Good Health Weekly from NCDC's latest report showed that a total of 377 suspected cases were reported from seven states and the majority were from Kano state.
Sadly, while experts harp on adequate immunisation coverage against the disease, statistics from the national Primary HealthCare Development Agency, showed that Nigeria's immunisation coverage has been poor and fluctuating significantly despite some improvement recorded in the past five years.
Since 2020, immunisation programmes in Nigeria have suffered losses due to the disruption by COVID-19 and response activities for other infectious diseases.
With immunisation programmes disrupted, many children missed out on vaccination at the time they should have gotten them. This undoubtedly widened the already gaps in the country which provided ideal conditions for the disease outbreak.
With 21 states already affected, the latest report from NCDC showed that out of the total of 1,064 suspected cases, Kano state remains the epicentre with 843, followed by Yobe with 86.
Other states include; Katsina 46, Lagos 22, Sokoto 14, and Zamfara 13.
Of the 1,064 suspected cases reported, 389 (36.6 percent) were confirmed (45 were lab confirmed, 343 were clinically compatible and 1 was epidemiologically linked), 322 (30.3 per cent) were discarded, 201 (18.9 per cent) are pending classification and 152 (14.3 per cent) are unknown.
The report also stated that the confirmed cases were distributed across 24 LGAs in six States. A majority (305 [78.4 per cent]) of the confirmed cases occurred among children aged 2 – 14 years.
A total of 62 deaths were recorded among all confirmed cases (CFR: 15.9 per cent). Only 60 (15.4 per cent) out of 389 confirmed cases were fully vaccinated with a diphtheria toxin-containing vaccine.
One state in Nigeria that is worst hit is Kano State with a total of 843 suspected cases. Out of which 360(45.9 per cent) were females and 423(54 per cent) were males as of 2nd march 2023, according to the State Case Manager, Dr. Salma Ali Suwaid.
During the same period, Kano recorded a total of 61 deaths with a Case Fatality Rate CFR of 12.2 per cent and 83 per cent of deaths occurred in patients with onset of symptoms greater than 3 days.
However, Diphtheria, according to, the World Health Organisation, has been one of the most feared childhood diseases, characterised by devastating outbreaks throughout history.
Also, studies have shown that vaccination against diphtheria has dramatically reduced the mortality and morbidity of diphtheria; however, diphtheria is still a significant child health problem in countries with poor routine childhood immunisation coverage like Nigeria.
Specifically, the NCDC in one of its reports stated that the prevention of infection controls diphtheria through high population immunity achieved by high vaccination coverage. Also, Infectious disease experts say Diphtheria outbreaks occur due to poor vaccination coverage
Today, findings from the National Primary Health Care Development Agency, NPHCDA, showed that Nigeria experienced very low Routine Immunisation, RI, and coverage up to 2016. Nigeria in 2016 recorded 33 per cent in immunisation coverage. The poor coverage led to the Federal government's declaration of a state of emergency on Routine Immunisation in 2017 and led to the establishment of NERICC, SERICC & LERICC in 18 poor-performing states.
Following the effort, Nigeria moved from 33 per cent coverage to 57 per cent, according to the Multiple Indicator Cluster Survey, MICs, 2018 while the SMART survey conducted that year rated Nigeria 50 per cent.
In 2019, according to the SMAR survey, the country recorded an improvement of 71 per cent. Unfortunately, in 2021, the gains in 2019 were lost as coverage plunged downward by 57 per cent according to the 2021 MICS.
Giving further insight into the gains achieved following the introduction of the different programmes designed to improve immunisation coverage in Nigeria, Dr Bassey Okposen from the National Primary Healthcare Agency, explained that 33 (89 per cent) of 36 states including the Federal Capital Territory, FCT, recorded an increase in Penta 3 coverage with the most significant improvement recorded in Yobe, Ebonyi and Kebbi States.
Okposun in a presentation tagged: "Vaccination Response to the Ongoing Diphtheria Outbreak in Nigeria: What We Need to Know" also said seven states achieved at least 80 per cent target immunisation coverage in 2021 MICS/NICS with the highest coverage reported in Ebonyi where there was a 45 per cent-pt increase in coverage from 54 per cent in 2015 to 99 per cent in 2021.
He said 4 (11 per cent) of 36 states plus FCT recorded a decline in Penta coverage with the most significant decline in Borno with 18 per cent.
Experts say without adequate immunisation, childhood diseases like diphtheria will continue to pose a threat in the country.
In the views of an Infectious Disease Physician at the Niger Delta University Teaching Hospital (NDUTH), Okolobiri, Bayelsa State, Prof. Dimie Ogoina, diphtheria is re-emerging in Nigeria due to significant gaps in childhood vaccination. He said inadequate, or failure of vaccination programmes in Nigeria underlies the challenge.
Ogoina, who is also the President of the Nigeria Infectious Disease Society, NIDS, warned that Nigeria will likely see resurgence if the immunisation coverage challenge is not addressed.
"The 2023 outbreak in Nigeria might be related to a recent drop in vaccination coverage in affected states and good clinical suspicion by clinicians who made an initial diagnosis of the outbreak.
"Diphtheria vaccines are largely effective and protective as long as the complete 3 doses are given during childhood. Children less than 5 years are at greater risk of diphtheria if they are not vaccinated or are under-vaccinated. Rarely, diphtheria can occur in fully vaccinated persons due to vaccine failure. In this case, it is either the vaccine did not work because of certain factors in the individual or the vaccine was already defective before administration due to poor storage and other factors.
Ogoina said the major challenges are related to inadequate subnational ownership and investments in the outbreak, the inadequate laboratory diagnostic, and treatment capacities in many hospitals across Nigeria, poor index of suspicion among health workers, and poor health-seeking behaviour among the general population.
To address the challenges of diphtheria, he said governments at all levels must take full ownership and invest in improving childhood vaccination coverage.
Noting that the NCDC, was working together with various stakeholders, responding to the outbreak by strengthening surveillance, diagnosis, and treatment, he said health workers' training and sensitisation were ongoing.
"The NCDC and the NPHCDA are central to the control of Diphtheria. These agencies should be supported to scale up preventive and response efforts, including risk communication and community engagement, to improve vaccine acceptance and promote early diagnosis and appropriate treatment."
What you should know about the diphtheria vaccine
Diphtheria is a disease that affects most people without a vaccine. The Diphtheria vaccine is a bacterial toxoid, ie. a toxin whose toxicity has been inactivated.
The vaccine is normally given in combination with other vaccines, including tetanus and pertussis (e.g. DTwP/DTaP, pentavalent vaccine).
For adolescents and adults, the diphtheria toxoid is frequently combined with tetanus toxoid in lower concentration (Td vaccine).
The WHO recommends a 3-dose primary vaccination series with a diphtheria-containing vaccine followed by 3 booster doses.
The primary series should begin as early as 6 weeks of age with subsequent doses given with a minimum interval of 4 weeks between doses.
The 3 booster doses should preferably be given during the second year of life (12-23 months), at 4-7 years, and at 9-15 years of age. Ideally, there should be at least 4 years between booster doses.
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