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Year : 2021  |  Volume : 65  |  Issue : 1  |  Page : 60-63  

Trend, morbidity profile and immunization status of diphtheria admitted cases: A 5-years review from a sentinel centre in Kolkata

1 Associate Professor, Department of Community Medicine, Murshidabad Medical College, Murshidabad, West Bengal, India
2 Assistant Professor, Department of Community Medicine, I.D and B.G. Hospital, Kolkata, West Bengal, India
3 Principal, Department of Community Medicine & Principal, I.D. & B.G. Hospital, Kolkata, West Bengal, India
4 Professor and H.O.D, Department of Community Medicine, Midnapur Medical College, Midnapur, West Bengal, India

Date of Submission28-Feb-2020
Date of Decision21-Apr-2020
Date of Acceptance21-Jul-2020
Date of Web Publication20-Mar-2021

Correspondence Address:
Anima Haldar
Landmark- Calcutta Public School, Urban Sabujayan Complex, Flat No. 4, Building No. 100, P.O. Mukundapur, Kalikapur, Kolkata - 700 099, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijph.IJPH_148_20

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Despite strengthening of the universal immunization program, diphtheria remains endemic in India. Diphtheria is under surveillance for vaccine-preventable diseases of the World Health Organization and also in India. The present record-based retrospective study was conducted on 241 confirmed diphtheria patients admitted in an infectious disease hospital of Kolkata over 5 years (2015–2019) with the objectives of assessing the admission trend, immunization status, and outcome of patients. Among the patients, majority (57.3%) were female; 50.6% were ≥15 years; 49.0% resided in rural areas. Five-year admission rate did not show any declining trend. Major number of cases occurred in 2016; another peak observed in 2019. Only 27.4% fully immunized rest either partiality immunized (44.4%) or nonimmunized (28.2%). Overall, 54% of the patients developed any complications, and case fatality was 9.5%. Gradual age shift toward adults reiterated the widespread use of adult immunization with Td vaccines. Early reporting to the hospital is necessary to reduce complications and case fatality.

Keywords: Case fatality rate, complication, diphtheria, immunization, trend

How to cite this article:
Ray SK, Maji B, Haldar A, Baur B. Trend, morbidity profile and immunization status of diphtheria admitted cases: A 5-years review from a sentinel centre in Kolkata. Indian J Public Health 2021;65:60-3

How to cite this URL:
Ray SK, Maji B, Haldar A, Baur B. Trend, morbidity profile and immunization status of diphtheria admitted cases: A 5-years review from a sentinel centre in Kolkata. Indian J Public Health [serial online] 2021 [cited 2021 Sep 20];65:60-3. Available from:

Diphtheria epidemiology has been changing worldwide. Re-emergence of diphtheria is occurring in many countries, largely attributable to low vaccine coverage and waning vaccine immunity in adolescents and adults.[1] Indian subcontinent and South-East Asia account a substantial proportion of global diphtheria burden.[2] During 2001–2015, India reported nearly 50% of global diphtheria occurrence.[1] In 2017, India reported 5293 cases to the WHO; mostly in nonimmunized patients.[2]

A majority of diphtheria cases were seen in persons aged above 15 years, while older adults suffered with high case fatality rate (CFR).[3] Diphtheria mortality increases with delay in administration of antitoxin (antidiphtheria serum [ADS]). CFR of respiratory tract diphtheria ranges between 2% and 20%, with average of 10%.[2]

According to the national level surveys, coverage of three primary doses of diphtheria containing vaccines during 2001–2016 was 78.4%.[1] However, neither infection nor primary vaccination confers long-lasting immunity. Revaccination of adults every 10 years with age-appropriate doses of diphtheria containing vaccine is necessary to sustain immunity. India has replaced the adult TT vaccine with Td in 2019 and launched VPD surveillance.[2]

Hospital-based surveillance and hospital records play a crucial role in identifying current diphtheria epidemiology. Therefore, the present study was undertaken in a specialized referral infectious diseases (IDs) hospital with the objectives of assessing the trend of occurrence of diphtheria, morbidity profile, and immunization status of admitted patients.

This was a hospital record-based descriptive, observational study conducted over a 6-month study period (August 2019 to January 2020). Diphtheria patients admitted in a state level ID hospital during the past 5 years, from January 2015 to December 2019, were taken as the study sample. The total enumeration technique was followed to include all 241 patients admitted with clinical features suggestive of diphtheria, who received treatment with ADS and improved subsequently. A total of 1488 patients were admitted with diphtheria-like clinical features during the past 5 years, but those 1247 cases who recovered without ADS were excluded. In this hospital, diphtheria cases were diagnosed mainly clinically. Throat swab samples were sent to the laboratory for culture to identify Klebs-Loffler bacillus to support the diagnosis. However, in majority of the cases, laboratory confirmation was not possible probably due to the reason that patients presented to this referral ID hospital usually after getting antibiotic treatment which inhibits the growth of bacilli in the culture medium. Hence, only those cases that received ADS and improved subsequently were considered as confirmed diphtheria for this study purpose.

Those patients who had received 3 primary immunization doses of diphtheria containing vaccine according to UIP were considered as “fully immunised,” those who received 1 or 2 primary doses were considered as “partially immunised,” and those who had not received any doses or whose vaccination status was unknown were taken as “nonimmunised.”

Retrospective analysis of the inpatient hospital database was done after obtaining necessary permission from the Institutional Ethics Committee with reference no. IDBGH/Ethics/2559, dated: 12.06.2019. Bed head tickets of all the 241 patients were reviewed from the hospital wards and record section to retrieve information regarding patients' demographic profile, time of admission, vaccination status, and subsequent major events including the development of complications and outcomes. Collected data were entered in MS Excel, analyzed, and presented in the form of proportions and diagrams.

Out of a total 241 diphtheria patients admitted over the past 5 years, 103 (42.7%) were male, 138 (57.3%) were female. Patients aged below 15 years constituted 49.4% and rest 50.6% were aged 15 years and above, as shown in [Table 1]. There was a statistically significant difference (χ2 = 20.558, P < 0.05, df = 2) between male and female distribution of diphtheria patients aged below 15 years, 15–30 years and >30 years.
Table 1: Age group-wise distribution of diphtheria cases according to demographic variables, immunization status, and complications (n=241)

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Among the study population, 68% were Hindus and rest 32% were Muslims. Majority of the patients (49.0%) were from rural area, followed by urban area (29.5%) and rest (20.3%) from semi-urban area. Few patients (1.2%) were also admitted from the adjoining states, e.g., Jharkhand as referred cases.

The occurrence of diphtheria in relation to patients' previous vaccination history with diphtheria containing vaccine revealed that 66 (27.4%) were fully immunized, 107 (44.4%) were partially immunized, and 68 (28.2%) patients were either nonimmunized or of unknown vaccination status. Among patients under 15 years of age group, partially immunized (21.2%) was more compared to fully immunized (19.1%), whereas in 15–30 years' age group, partially immunized patients were highest (20.3%) in comparison to fully immunized (7.5%) and nonimmunized (8.3%), whereas, in above 30 years' age group nonimmunized was highest (10.8%) and fully immunized was the least (0.8%) as depicted in [Table 1].

[Table 1] also describes different types of complications developed among the admitted cases; 111 (46.1%) patients did not develop any complications and recovered well. Rest 130 (53.9%) patients developed complications, out of which major complication was myocarditis (29.8%), followed by both myocarditis and palatal palsy (12%), respiratory distress syndrome (7.1%), and only palatal palsy (5%).

Case fatality was noticed in 23 (9.5%) patients due to diphtheria-related complications.

[Figure 1] indicates year-wise admission trend of diphtheria cases from January 2015 to December 2019. Male diphtheria cases were more or less same in the years 2015 and 2016, followed by sharp decline in 2017 and again inclining in the year 2019. Diphtheria among female patients showed two peaks; the highest number of cases (42) was noticed in 2016 and 2019.
Figure 1: Line diagram showing the admission trend of diphtheria cases over the past 5 years (N = 241).

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The present study revealed that females were affected more than males (M:F ratio 1:134). This finding did not corroborate with an earlier study done by Haldar et al.[3] in 2005 where the M:F ratio was equal. The occurrence of diphtheria was more or less same among under 15 years and ≥15 years' age group in the present study, whereas, Haldar et al.[3] found more patients in <15 years' age group compared to ≥15 years.

Majority of the patients were from rural area (49%), followed by urban (29.5%) and semi-urban area (20.3%). A similar finding was observed by Singh et al.[4] where 47% belonged to rural area. A previous study by Ray et al.[5] in West Bengal showed that the dropout rate for 2nd and 3rd dose of DPT vaccine in rural area was more compared to urban area.

The present study revealed that 27.4% of the patients suffered from diphtheria despite being fully immunized, whereas 44.4% of affected patients were partially immunized. Our study cohort of hospitalized diphtheria cases had much lower rate of full primary immunization coverage (27.4%) as compared to national average of 78.4% during 2001–2016.[1] The present study findings corroborated with Nandi R.[6] (30% patients were vaccinated), whereas Haldar et al.[3] and Sing et al.[4] found that much lower proportion of patients were fully immunized (15% and 12%, respectively). This variation might be due to lesser number of observations over a short period of time in the earlier studies.

The present study clearly indicated that female diphtheria cases outnumbered males. Admission trend over the last 5 years also showed repeated sharp incline in number of female cases during 2016 and 2019, whereas admission among males did not show any sharp rise. Probable reasons might be lesser immunization coverage among the female children due to negligence.

Earlier, a 5-year sentinel surveillance of diphtheria was undertaken in a rural medical college by Ray et al.[7] from 1989 to 1993, which found no significant change in trend of diphtheria cases in spite of high level of full immunization coverage. Trend analysis during 2015–2019 in the present study also revealed no change in overall diphtheria admission. Although another study from a sentinel center in Delhi by Singh et al.[4] found declining trend of diphtheria.

Among the admitted cases, 53.9% developed complications; majority (29.8%) were myocarditis, followed by both myocarditis and palatal palsy (12%), respiratory distress (7.1%), and palatal palsy (5%), whereas, Haldar et al.[3] reported that 67.3% of patients developed complications: myocarditis (47.7%), both palatal palsy and myocarditis (10.3%), only palatal palsy (6.5%), and respiratory distress (2.8%).

CFR of 9.5% was observed in the present study, which was quite high, probably because this state level ID hospital received a majority of the diphtheria patients as referred cases from other hospitals and usually at a late stage of disease progression. A similar observation was found by Quick et al.[8] in Georgia where CFR was 10.3% among hospitalized patients; associated with partial or nonimmunization, being a rural resident and being referred late after the onset of symptoms. Much higher CFR was reported by Nandi et al.[6] (16%) and Singh et al.[4] (32%).

The present study revealed that the occurrence of diphtheria cases in above 30 years' age group was more among nonimmunized patients, whereas, the proportion of nonimmunized diphtheria patients in <30 years' age group was relatively less. This might be due to the beneficial effect of the implementation of UIP in 1985, nearly 35 years ago.

The present study indicated that diphtheria was also prevalent among immunized adolescents and adults, in addition to partially immunized and nonimmunized individuals, probably due to waning of immunity with age. Strict implementation of policy regarding adult vaccination and timely booster doses is the need of the hour along with full immunization coverage of all children. Early reporting to the health facility and prompt initiation of specific treatment is needed to reduce grave complications and mortality. Proper implementation of VPD surveillance throughout the country will be helpful to combat diphtheria-related problems.

This was a hospital record-based study; thus, the community burden of diphtheria cannot be measured, and any association with patient's sociodemographic status could not be established.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Murhekar M, Epidemiology of diphtheria in India, 1996–2016: Implications for prevention and control. Am J Trop Med Hyg 2017;97:313-8.  Back to cited text no. 1
Surveillance for Vaccine Preventable Diseases Diphtheria, Pertussis and Neonatal Tetanus, India Field Guide. 1st ed. Delhi: Printed for Ministry of Health and Family Welfare, Government of India; 2019. p. 5-20.  Back to cited text no. 2
Haldar A, Malay M, Haldar S, Rana R, Chatterjee S, Soren AB. A study on determinants of occurrence of complications and fatality among diphtheria cases admitted to ID &amp; amp; BG Hospital of Kolkata. J Commun Dis 2008;40:53-8.  Back to cited text no. 3
Singh J, Harit AK, Jain DC, Panda RC, Tewari KN, Bhatia R, Sokhey J. Diphtheria is declining but continues to kill many children analysis of data from sentinel center in Delhi, 1997. Epidemiol Infect 1999;123;209-15.  Back to cited text no. 4
Ray SK, Haldar A, Biswas B, Chatterjee T, Misra RN, Bagchi S, et al. A comparative study of immunisation status of children in West Bengal. J Commun Dis 1998;30:205-8.  Back to cited text no. 5
Nandi R, De M, Browning S, Purakayastha P, Bhattacharjee AK. Diphtheria: The patch remains. J Laryngol Otol 2003;117:807-10.  Back to cited text no. 6
Ray SK, Mallick S, Prasad MS, Pankaj M, Satish K. An epidemiological study on incidence, symptoms and complications of measles in bordering districts of West Bengal. J Commun Dis 2018;40:59-64.  Back to cited text no. 7
Quick ML, Sutter RW, Kobaidze K, Malakmadze N, Strebel PM, Nakashidze R, et al. Epidemic diphtheria in republic of georgia, 1993-96: Risk factors for fatal outcome among hospitalized patients. J Infect Dis 2000;181 Suppl 1:S 130-7.  Back to cited text no. 8


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