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Research Article

A Cross-sectional Study on Hepatitis B 
Immune Status Among Vaccinated 
Healthcare Workers in Khartoum, Sudan
Abdullahi Elsheikh Mahgoub1*, Yassir Hamadalnil2, Osama Mohammed3, 
Rasha Nakhleh4,5, and Musa Mohamed Khair6

1. Geriatric Fellow, Hurley Medical Center, Flint, Michigan, USA
2. Department of Clinical Microbiology, Faculty of Medicine, Nile University, Khartoum, Sudan
3. Central laboratory, Khartoum, Sudan
4. Geriatric Fellowship Program/Hurley Medical Center
5. College of Human Medicine, Michigan State University
6. Medicine, University of Khartoum, Khartoum, Sudan

Abstract

Background: Hepatitis B virus (HBV) infection can lead to chronic hepatitis, liver 
cirrhosis, and Hepatocellular Carcinoma (HCC). Vaccination against the virus plays an 
important role in its prevention. Health personnel at risk of infection are recommended 
to receive the vaccine and to check their immune status thereafter.
Objective: To determine Hepatitis B Immune status among vaccinated health 
personnel in Khartoum state, Sudan. A total of 106 health personnel from different 
hospitals and doctors’ mess in Khartoum and from different jobs were surveyed 
and their HBV surface antibodies levels were determined by HBsAb (Quantitative) 
ELISA Kits.
Methods: Of the 106 participants in this study, the majority were females 72.6%. 
The mean age of those involved was 27.69 years, and nurses made for more 
than 50% of those surveyed. About 56.6% (60) of the health personnel involved 
took three or more doses of HBV vaccine while the rest received one or two 
doses. The results of the participants who received three or more doses of 
the vaccine represented immunity by 70%. In general, about 47.2% (50) of the 
participants in this study did show excellent immune response (>100 mIU/mL) 
and 18.9% (20) had weak protective levels (between 10 and 100 mIU/mL) 
So, we concluded that HBV post-vaccination immunity status of health personnel 
in Khartoum state is lower than post-vaccination HBV immunity in other parts of the 
world. There is an urgent need for a national protocol of HBV vaccination to improve 
the immunization status of health personnel with a regular checkup of HBV immunity 
and easy access to a good-quality vaccine.

Sudan Journal of Medical Sciences 
Volume 15, Issue no. 1, DOI 10.18502/sjms.v15i1.6700
Production and Hosting by Knowledge E

How to cite this article: Abdullahi Elsheikh Mahgoub (2019) “A Cross-sectional Study on Hepatitis B Immune Status Among Vaccinated  Healthcare 
Workers in Khartoum, Sudan”, Sudan Journal of Medical Sciences, vol. 15, issue no. 1, pages 35–42. DOI 10.18502/sjms.v15i1.6700

Corresponding Author: 

abdullahimahgoub@hotmail.com.

Received 18 January 2020

Accepted 07 March 2020

Published 31 March 2020

Production and Hosting by 

Knowledge E

 cc Abdullahi Elsheikh 

Mahgoub. This article is 

distributed under the terms 

of the Creative Commons 

Attribution License, which 

permits unrestricted use and 

redistribution provided that 

the original author and source 

are credited.

Editor-in-Chief:

Prof. Mohammad A. M. Ibnouf

Key words: Hepatitis B vaccines; healthcare workers; immune response



Sudan Journal of Medical Sciences Abdullahi Elsheikh Mahgoub et al.

DOI 10.18502/sjms.v15i1.6700 Page 36

Introduction

Hepatitis B Virus (HBV) is a member of the Hepadnaviridae family with a small DNA 

virus and unusual features of replication similar to retroviruses, in which HBV can 

replicate through an RNA intermediate and forming a stable minichromosome (cccDNA) 

in the nucleus. These features of the HBV replication cycle give it the ability to persist in 

infected cells [1]. HBV can cause acute hepatitis and can also lead to other more serious 

complications like Chronic Hepatitis, Liver Cirrhosis, and Hepatocellular Carcinoma 

(HCC) [2]. HBV can survive outside the body for up to seven days; the virus incubation 

period is around two and a half months. The virus can be transmitted perinatally from 

a mother to her baby, horizontally by exposure to infected blood or blood products, or 

through direct spread percutaneously or to mucosal membranes [3]. HBV infects more 

than 300 million people worldwide; Sudan is classified among the countries with high 

HBV seroprevalence. Exposure to the virus varied from 47 to 78%, with a hepatitis B 

surface antigen prevalence ranging from 6.8% in central Sudan to 26% in southern 

Sudan [4]. HBV vaccine is a recombinant DNA vaccine that contains HBsAg genetically 

engineered from the yeast Saccharomyces cerevisiae. It provides a seroprotection rate 

of 85–100% that was seen one month after the last dose of vaccine and it confers 

immunity for at least 10 years [5]. Hepatitis B vaccine is recommended for unvaccinated 

adults who are at risk for HBV infection like people whose sex partners have hepatitis B, 

sexually active persons who are not in a long-term monogamous relationship, persons 

seeking evaluation or treatment for a sexually transmitted disease, men who have sex 

with men, people who share needles, syringes, or other drug-injection equipment, 

household contacts of HBV-infected persons, health personnel and public safety 

workers at risk for exposure to blood or body fluids, residents and staff of facilities for 

developmentally disabled persons, persons in correctional facilities, victims of sexual 

assault or abuse, travelers to regions with increased rates of hepatitis B, people with 

chronic liver disease, patients on hemodialysis, HIV infection, or diabetes, and anyone 

who wants to be protected from HBV. The vaccine is usually given as three shots over 

a period of a six-month period [6]. Serum antibody to the hepatitis B surface antigen 

(anti-HBs) has long been established as a marker of vaccine-induced protection against 

hepatitis B. An anti-HBs level of ≥10 IU/ml has been suggested to indicate protection 

against hepatitis B disease [7]. Old age in adults, male gender, increased body mass 

index, smoking, and concomitant disease are some of the factors that may decrease 

the immunologic response to HBV vaccine [8]. This study was conducted to determine 

hepatitis B immune status among vaccinated health personnel in Khartoum, Sudan.



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Materials and Methods

This is a descriptive cross-sectional study conducted at public hospitals of Khartoum 

including the Ibn Sina Specialized Hospital, the Alshaab Teaching Hospital, and the 

Academic Hospital from 30th July to 30th September 2017. The study included healthcare 

providers working in all departments, including trained nurses, medical attendants, and 

clinicians – both surgical and medical-related specialties and laboratory technicians. 

The investigator approached healthcare workers through the hospital administration 

and the heads of the departments. A self-administered questionnaire that covered 

age, gender, job description, total doses of vaccine and the date of the last dose plus 

other data such as duration since the last dose and a history of immunosuppressive 

treatment and blood transfusion was used to obtain information from the participants. 

The questionnaires were collected from the healthcare workers upon completion by 

appointment with the participant; 5 ml venous blood sample was collected from the 

cubital vein under complete possible aseptic conditions in EDTA containers, centrifuged 

at 3000 rounds per min for 10 min to be separated and stored at –20ºC till it was used.

The ELISA procedure was followed according to the manufacturer’s instructions. 

In brief, 50 μl of the serum were incubated at 37ºC for 60 min in 118-well microplate 

coated with HBsAg reactive to HBsAb (anti-HBs). Subsequently, the wells were washed 

(three times) to remove residual serum. 50 μl of anti-HBs conjugated AB was added and 

incubated at 37ºC for 60 min. The wells were washed (three times) to eliminate unbound 

conjugate, 50 μl of enzyme-substrate and chromogen were added and incubated at 

37ºC for 60 min; 50 μl diluted stop solution (Sulphuric acid) was added and the plate 

was read at 450 nm as indicated by the manufacturer.

Interpretation of the result

The cut-off value was estimated by calculating the mean (m) absorbance value of 

negative control x 2.1.

Cut-off = mean of the negative control x 2.1

For the validity of the accomplishment, the following is required:

(a)  Negative control means: absorbance of individual negative control values must 
be <0.9

(b) Positive control means: it must be >1.1
(c)  Equivocal means: absorbance of individual equivocal values must be between 0.9 

and 1.1. All statistical calculations were done using SPSS for Windows, version 24.



Sudan Journal of Medical Sciences Abdullahi Elsheikh Mahgoub et al.

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Results

A total of 106 health personnel participated in this study, of those, 77 (72.6 %) were females 

and 29 (27.4%) males with a female:male ratio of 2.65:1. The mean age of the participants 

was 27.69 years, the minimum age was 20 years, and the maximum age was 55 years.

Furthermore, 56 (52.8%) participants were nurses by profession, 35 (33%) were 

doctors, 4 (3.7%) lab technicians, and 11 (10.4%) others. 

About 97 (91.5%) participants took the last dose of vaccine within the past 10 years 

and 12 (11.3%) took their vaccine during childhood. 

The number of subjects who completed the all three doses of vaccine or more were 

60 (56.6%), those who took two doses were 23 (21.7%), and those with only one dose 

were 23 (21.7%), see Table 1. 

Table 1: Total Number of HBV Vaccine Doses Received vs Immunity Acquired After Each Dose.

Number of HBV Vaccine 
Doses Received

Frequency Percent Valid Percent

1 dose 5.20 + 1.31 4.28 + 0.88 0.0076

2 doses 2.03 + 1.43 1.26 + 0.76 0.0271

3 doses 3.06 + 0.73 2.60 + 0.56 0.0248

>3 doses 1.12 + 0.29 1.20 + 0.24 0.2736

Total 106 100% 100%

Sixty participants completed the three or more doses of vaccine, about forty two 

(66%) had HBsAbs titer ≥10 mIU/mL and eighteen (30%) had titer <10 mIU/mL. Of those 

who took two doses of the vaccine, 17 (73.9%) had HBsAbs titer >10 mIU/L and 6 (26.1%) 

<10 mIU/mL. And of those who received one dose, 12 (52.1%) had titer <10 mIU/mL and 

11 (47.8%) ≥10 mIU/mL (Figure 1).

About 34 (32%) participants were exposed to needle stick injury during their work 

but didn’t received treatment, 3 (8.8%) had undergone blood transfusion, and 1 had 

received Hepatitis B Immunoglobulin after accidental needle injury from Hepatitis 

B-infected patient and her HBsAb result was excellent at 191.0 mIU/mL (Figure 2).

Discussion

HCWs are at a higher risk of blood-borne infections, especially HBV. Vaccination is 

effective in protecting 90–95% of adults [9]. According to the World Health Organization 

(WHO) estimate, hepatitis B vaccination coverage among healthcare workers varies 

from 18% being lowest in Africa to the highest 77% in Australia and New Zealand [10]. 



Sudan Journal of Medical Sciences Abdullahi Elsheikh Mahgoub et al.

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Figure 1: Distribution of Subjects Participating in this Study According to Specialty in Which Nurses (56) 
Were More than all the Other Groups.

Figure 2: Correlation Between HBsAb Titer and Number of Participants Receiving Different 
Doses of HBV Vaccine (p = 0.035).

In this study, we examined the level of anti-HBsAb in healthcare personnel in three 

public hospitals in Khartoum state besides Khartoum doctors’ mess; the hospitals were 

the Ibn Sina Specialized Hospital, the Alshaab Teaching Hospital, and the Academic 

Teaching Hospital. They were chosen mainly because of their easy accessibility. In this 

study, 60 (56.6%) participants completed all three doses of vaccine, which is higher 



Sudan Journal of Medical Sciences Abdullahi Elsheikh Mahgoub et al.

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compared to the lower vaccination rates found in the other two studies conducted in 

Ethiopia, one in the Gondar University Hospital (28.7%) [11] and the other at the Adama 

General Hospital and Medical College (25.6%) [12] while nearly similar results as ours 

was seen in a study conducted in the Makueni County of Kenya (48%) [13]. Another 

study reveals a higher percentage of full vaccination (72%) in Libya [14]. 

From our results, we notice that there is a direct relationship between the numbers of 

doses the participants received and their immune status against HBV (p = 0.035), so those 

who received three or more doses of the vaccine, their results represented immunity by 

70%. On the other hand, just 47.8% of those who took one dose of HBV vaccine in their 

lifetime are immune to the virus (Table 1). In our study about 70% of the subjects were 

immuned after receiving at least three doses of the vaccine which is lower than the study 

done in West Pomeranian Region of Poland (94.5%) [15]. Another finding in this study was 

that there is no big difference in HBV immunity between those who took their last dose 

of the vaccine <10 years ago (64.95% are immune) and the participants who took their 

last vaccine dose ≥10 years ago (77.8% are immune). In general, about 47.2% (50) of the 

participants in this study did show excellent immune response (>100 mIU/mL), 18.9% (20) 

had weak protective levels (between 10 and 100 mIU/mL) which in comparison to the 

Lasemi, Eshagh et al’s study, were a little bit higher as in their study, 54% of the students 

had an excellent protective immune response and 24.2% had a positive but weak immune 

response [16]. Some suggest that the weak immune response among health personnel 

in Sudan may be due to the type of vaccine that is used, which is an imported vaccine 

from outside the country. No official data about the type of vaccine are available from the 

National Medical Supplies Fund (NMSF). Only 56.6% of the involved health personnel 

finished the recommended three doses that reflects the gap in the health education and 

awareness about HBV vaccination among health personnel. This may be due to the high 

cost and lack of a public protocol for health personnel HBV vaccination, we found only 

two previous researches close to this topic in Sudan [17]. It is worth mentioning that most 

participants 56 (52.8%) were nurses, who were more willing to get involved and check 

their HBsAb levels than doctors. 

About 70 (66.0%) participants were surveyed at the Ibn Sina Hospital; they were 

eager to get involved because they wanted to know their immune status against HBV as 

the hospital is the main referral hospital for gastroenterology and hepatology in Sudan. 

They have better awareness about the importance of vaccination against the HBV and 

their increased risk of acquiring the disease if they don’t have immunity against the 

virus especially with the high numbers of hepatitis B patients in their hospital. 



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Conclusion

From this research, we can conclude that HBV post-vaccination immunity status of 

health personnel in Khartoum state is lower than the post-vaccination HBV immunity 

in other parts of the world. So, there is an urgent need for a national protocol of HBV 

vaccination to improve the immunization status of healthcare workers that includes 

regular checkups of HBV immunity and easy access to a good-quality vaccine. 

To get more accurate results of the response to the hepatitis B vaccine among 

healthcare workers in Sudan, more large-scale studies should be conducted. 

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