ORIGINAL

Niger J Paed 2014; 41 (2): 104 –109

Sadoh AE

Sadoh WE

Does Nigeria need the birth dose of

the hepatitis B vaccine?

DOI:http://dx.doi.org/10.4314/njp.v41i2,5

Accepted: 26th November 2013

Abstract: The control of hepatitis

B infection involves several strate-

gies of which the most effective is

vaccination. Schedules which in-

clude a birth dose (which can pre-

vent vertical transmission when

administered within 24 hours of

birth) are recommended for use in

countries with a high rate of verti-

cal transmission. Nigeria is highly

endemic for hepatitis B infection.

Nigeria had hitherto utilized the

monovalent HBV vaccine in the

three dose schedule that includes a

birth dose, the recent introduction

of an HBV containing pentavalent

vaccine (which cannot be adminis-

tered at birth) calls to question

whether there should be continued

use of the birth dose of HBV

are seropositive for HBsAg and

HBeAg. Maternal to child trans-

mission rates of HBsAg of 47-

53.3% have been documented

while a significant proportion of

newborns were noted to have sero-

logical markers for HBV infection

before receiving their first immu-

nization. These data indicate that

there is a significant potential for

vertical transmission of HBV in

Nigerian infants providing a com-

pelling reason for the continued

use of the birth dose of the HBV

vaccine. Cost-effectiveness was

not examined in this review.

There are, however, challenges to

the universal delivery of the birth

dose in a timely fashion. Encour-

aging institutional delivery, routine

screening of pregnant women

(with the administration of HBV

within 24 hours of birth to infants

of seropositive mothers), retraining

of health care workers on ensuring

the timely receipt of the birth dose

of HBV vaccine and health educa-

tion of mothers and the community

on the need for immunization

within 24 hours of birth are sug-

gested strategies to improve the

timely uptake of the birth dose of

HBV

Sadoh AE (

Sadoh WE

)

Department of Child Health

University of Benin Teaching Hospital

PMB 1111. Benin City,

Edo State, Nigeria.

Email: ayebosadoh@yahoo.com

(

using the monovalent vaccine) in

addition to three doses of the pen-

tavalent vaccine given subse-

quently. This is given the fact that

most infections in Nigeria are

reportedly acquired in childhood

through horizontal rather than ver-

tical transmission. There is also the

question of cost- effectiveness of

the four dose schedule compared to

the three dose schedule in the set-

ting of Nigeria’s hepatitis B epide-

miologic profile.

A review of the available evidence

indicates that a significant propor-

tion of Nigerian women of child

bearing age and pregnant women

Keywords: Birth dose, Hepatitis B

vaccine, Nigeria, Infants

5

,6

Introduction

increases. These studies did not however determine

the contribution of vertical transmission. In Asia- Pacific

region half of the chroni₇c hepatitis B burden results

from vertical transmission.

Hepatitis B virus (HBV) infection is a worldwide public

health problem. About a third of the world population

1

has been infected wh₁ile about 350 million persons are

chronically infected. Approximately 15-40% of in-

fected persons will develop cirrhosis, liver failure or

The main strategy for prevention of HBV is vaccina-

tion. For vaccination to be effective in preventing verti-

8

2

hepatocellular cancer. HBV related deaths are about

cal tran₁smission a birth dose of the HBV vaccine is re-

quired. Nigeria had since 2004 utilised monovalent

HBV vaccine in providing₉ three doses of HBV immuni-

zation starting at birth. In providing immunization

against Haemophilus influenza type B a pentavalent

vaccine comprising DPT, HBV and HiB was introduced

to replace the trivalent DPT and monovalent HBV in

6

of death worldwide. Nigeria is highly endemic for the

hepatitis B virus and most infections are reportedly ac-

00,000 annually ma_,₃king HBV the tenth leading cause

2

4

quired in childhood through horizontal transmission. In

Nigerian studies, lower prevalence of hepatitis B has

been found in infants with prevalence increasing as age

1

05

1

0

2

012. The pentavalent vaccine is administered as three

of infected individuals, intravenous drug users, health

care workers, homosexua₈ls and individuals with

multiple sexual partners.

doses commencing at the age of six weeks. Since the

pentavalent vaccine cannot be given at birth Nigeria has

continued to use the monovalent HBV vaccine to pro-

vide the birth dose of HBV vaccine. But does Nigeria

need the birth dose of the HBV vaccine if infections are

acquired horizontally? The World Health Organization

recommends that in countries where a lower proportion

of chronic HBV infection is acquired perinatally (e.g. in

Africa) the administration of a birth dose may be consid-

ered after evaluating the relative contribution of perina-

tal HBV to the overall disease burden and the feasibility

Vertical transmission is dependent on the presence of

1

HBeAg in mothers. Mothers who are HBeAg seroposi-

tive are 70-90% likely to transmit the infection to their

babies compared to 5-20% of mothers who are HBeAg

1

negative. Vertical transmission is the major route of

transmission in south East Asia where HBeAg seroposi-

tivity is high. In sub-Saharan Africa horizontal transmis-

sion is thought to be the commonest route of transmis-

sion with children becoming i₇nfected early in childhood

1

and cost effectiveness of providing a birth dose. This

article reviews the available evidence.

1

and during the school years. Newborn infection is un-

1

7

common in West Africa.

Epidemiology of Hepatitis B

The age at acquisition of HBV has important implica-

tions for outcome as infections acquired in infancy or

early childhood are more likely to become chronic.

About 80-90 % of infections acquired in the first year of

life become chronic while 30-50% of infections acquired

The HBV is a small DNA virus. Humans are the only

known natural host. It is a 42nm virus made up of the

8

surface antigen-HBsAg (which are 22nm spherical and

tubular particles) and the core antigen HBcAg. The com-

plete virion (Dane particle) comprises both the surface

and the core antigens. The virus also has the HBeAg

which is a soluble protein.

1

between 1-4 years of age become chronic. Infections

acquired in adulthood lead to chronicity in only2-5 % of

1

cases. Over time 25% of persons who acquire HBV as

children will develop primary liver cancer or cirrhosis as

2

The prevalence of HBV varies from region to region as

well as in different population groups. The level of en-

adults.

2

demicity of HBV is based on the level of seroprevalence

for HBsAg. Areas with HBsAg seroprevalence of

greater than 8% are regarded as highly endemic while

those with seroprevalence of 2-7% are considered to be

In Nigeria, children are believed to₁₈acquire most of their

4

infections horizontally. Eke et al in a recent publica-

tion however suggests that vertical transmission may be

the major route of transmission in Nigeria. Blood trans-

fusion is also considered a significant route of transmis-

sion but several studies have shown a lack of association

between blo₁₈o_,₁d₉ transfusion and being seropositive for

1

of intermediate endemicity. Areas with seroprevalence

1

of less than 2% have low endemicity. About 45% of the

world population live in areas that are highly endemic

1

for hepatitis B virus. These include south East Asia,

hepatitis B.

It has been suggested that this may be

Sub Saharan Africa, the Pacific Islands and the Amazon

basin. Areas of intermediate endemicity include Eastern

Europe and China while areas of low endemicity include

North America, Western Europe and Australia. Nigeria

is considered to be highly endemic for HBV as various

studies report seropr₁e₁_,v₁₂alence rates of 9.1-12% in the

due to improved blood transfusion practices.

Prevention of Hepatitis B Virus Infection

Hepatitis B virus infection is preventable. There are

various strategies for the prevention of hepatitis B.

These include vaccination, strict observance of universal

precautions and screening of blood and blood products

for Hepatitis B infection. Vaccination is the most effec-

tive tool in preventing the transmission of HBV infec-

general population

and 4.5-44.7% in chil-

5

,13,14

dren.

HBV is reported to contribu₅te to 58% of

1

chronic liver disease in a Nigerian study while another

study reported the presence of HB_,s₁A₆ g in 59.3% of

hepatocellular cancer cases in Nigeria.

2

tion. The HBV vaccine has been available and licensed

1

for use since 1982. There are various vaccination strate-

Transmission of hepatitis B and risk factors

gies. These include universal infant immunization,

screening of all pregnant women so that babies born to

those who are seropositive are offered the vaccine and

HBIG within 24 hours of birth, adolescent immunization

programme and targeted immunization of at risk groups

such as health care workers and intravenous drug users.

Improved blood transfusion practices have made the risk

of transfusion –transmitted HBV extremely rare in the

The HBV is transmitted through percutaneous and mu-

cous membrane contact with infected blood and other

1

,2

body fluids or contaminated sharp objects. The major

routes of transmission are vertically from an infected

mother to her baby, horizontally from child to child,

transfusion of unscreened blood and blood products,

sexually, use of contaminated sharp objects during pro-

cedures such as administering injections, surgery, dental

procedures, circumcision, tattooing,₁s_,₂c_,₄a_,r₈ifications, tradi-

2

0

United States of America. The United St₈ates of

America uses a combination of strategies.

tional uvulectomy and ear piercing.

Other potential

The World Health Organization recommended the inclu-

sion of the vaccine in all immunization programmes in

routes of transmission include sharing of tooth brushes

4

1

etc. Certain groups are considered to be at increased

1997. As at 2007 171 of the 193 WHO member states

risk of HBV infection. These include household contacts

had included the vaccine in their national childhood vac-

1

06

2

1

cination programmes. HBV vaccine alone given within

4 hours of birth has been shown to be 70-95% effective

prevalence of 8.9% w₂a₆s_,₂₇reported among women of child

bearing age in Lagos.

2

in preventing vertical transmission. The concomitant use

of HBIG also given within 24 hours of birth is 85-95%

effective in preventi₂ng both HBV infection and the

The presence of HBsAg in a significant proportion of

pregnant Nigerian women suggests that Nigerian infants

are indeed at risk of vertically acquiring the infection.

There have also been studies on HBeAg in the Nigerian

population. In a study of 572 HBsAg positive pers₈ons

2

chronic carrier state. The use of universal infant immu-

nization has reduced the prevalence of HBV related dis-

ease in countries where it has been introduced. Taiwan

reduced the prevalence of HBsAg from 9.8% to 0₃.6% 20

2

110(19.2%) were found to be positive for HBeAg. Of

those positive for the HBeAg the majority (81.8%) were

however males. In another study that compared pregnant

and non-pregnant women of child bearing age HBsAg

was found in 7.9% of₂p₉ regnant women and 7.6% of the

non-pregnant women. However, significantly more of

the seropositive pregnant women (62.5%) were also

positive for HBeAg compared to the non-pregnant

women. The authors did not have an explanation for the

significant difference. Another study on pregnant

women reported that 7.9% of those se₀ ropositive for

2

years after the introduction of the HBV vaccine. There

was also a reductio₂₃n in the incidence of hepatocellular

cancer in children. In Italy, after over 20 years of uni-

versal infant immu₄ nization HBsAg rates reduced from

2

1

3.4% to 0.91%. A common factor among all these

success stories is the fact that there was high coverage

for the vaccine.

Hepatitis B Vaccine Schedules

3

HBsAg were also positive for HBeAg. Although the

There are at least three different schedules recom-

mended by the World Health Organization for use in the

introduction of the HBV vaccine into childhood immu-

nization programmes (Table1).

prevalence of HBeAg, a marker of viral replication and

infectivity, which is also associated with higher vertical

transmission rates is not as high as reported in south

East Asia it nevertheless indicates the potential for sig-

nificant vertical transmission of hepatitis B in Nigerian

mothers.

1

Table 1: Hepatitis B vaccination schedules

Age

Visit

Hepatitis B vaccine Dosing schedules

3

1

In a study on mother infant pairs Onakewhor et al

I

II

III

reported a transmission rate of 42.86%. In a similar

study in south wes₂t Nigeria a transmission rate of 53.3%

Birth

1

HepB₁-

birth

HepB1₂

HepB2₂

HepB3

HepB₁-

birth

HepB2

3

2

1

3

was documented. In a study of Nigerian mothers and

6

1

weeks

0 weeks

4 weeks

2

3

4

DTP-HepB1₃

DTP-HepB2₃

DTP-HepB3

their children (under-fives) 4 of the 7 seropositive chil-

dren had mothers who were also seropositive while the

HepB3

6

mothers of the other 3 were seronegative. This study

1

Monovalent vaccine

could not however determine whether the transmission

was vertical or post natal. In another study that exam-

ined mother-child pairs 13.2% of the mothers were sero-

2

3

Monovalent or combination vaccine

Combination vaccine

3

positive while 6.9% of the children were seropositive.

Countries where vertical transmission is a major mode

of transmis₁sion are advised to use schedules that have a

birth dose. Nigeria adopted the three dose schedule

starting at birth, then at 6weeks and 14 weeks into its

immunization programme in 1995 and the vaccine be-

came widely available in 2004. In this schedule the

monovalent HBV vaccine was utilized. More recently in

Of the seropositive mothers 27.9% were also seroposi-

tive for HBeAg. 85% of the seropositive children were

born to HBsAg positive mothers while 77.7% of HBeAg

positive mothers had seropositive children. Although the

findings of this study suggest that the children acquired

the infections from their mothers it could not determine

whether the infections were acquired vertically or hori-

zontally.

2

012 Nigeria introduced the pentavalent vaccine which

comprises DPT,HBV and HIB. The pentavalent vaccine

replaced the trivalent DPT and monovalent HBV. The

pentavalent vaccine can only be commenced at 6 weeks

thus Nigeria has retained the birth dose of monovalent

HBV which is recommended to be given within the first

two weeks of life. The question is does Nigeria need the

birth dose of HBV if the major route of transmission is

horizontal?

A recent study on infants presenting for their first immu-

nization noted that serological markers₃₄ for HBV was

present in29.4 % of the studied infants. Most of these

infants did not also receive the HBV vaccine within 24

hours of birth suggesting that even though they eventu-

ally did receive the vaccine they may have already been

infected thereby constituting a waste of the vaccine. It is

however pertinent to note that the presence of these

markers do not necessarily mean infection as the mark-

ers may be a reflection of maternally transferred anti-

bodi₃e₅s_-₃₇and the infants may clear the markers eventu-

Hepatitis B in Women of Child Bearing Age and

Pregnant Women

Many studies in Nigeria have reported H₅BsAg sero-

2

ally.

That study as well as those on perinatal trans-

prevalence in pregnant women. Luka et al reported a

mission is limited by their cross-sectional design as they

could not determine if the infants with serological mark-

ers were eventually infected.

prevalence of 8.3% among pregnant women in Kadu₉na;

1

a similar prevalence was also reported by Eke et al in

pregnant women in Nnewi. In Benin City a prevalence

of 12.8% was reported also in pregnant women while a

1

07

Justification for the Birth Dose of Hepatitis B Vaccine in

Nigeria

Strategies to improve uptake of the birth dose of hepati-

tis B vaccine

The high HBsAg seroprevalence in pregnant Nigerian

mothers, the presence of HBeAg in a significant propor-

tion of HBsAg positive mothers and the study indicating

the presence of serological markers in infants before

receipt of their first immunization are compelling rea-

sons for Nigeria to continue to offer the birth dose of the

HBV to Nigerian infants. Also commencing immuniza-

tion at birth is a better option since it₃₄can prevent both

vertical and horizontal transmission. It should how-

ever, be administered within the recommended time

frame especially in infants of mothers who are positive

or whose status is unknown.

Several strategies are suggested to improve the uptake of

the birth dose of the HBV vaccine. These include en-

couraging institutional delivery. If mothers deliver in

health facilities then health care workers will be able to

administer the birth doses of the vaccine to babies deliv-

ered in their facilities. Health workers will need to be

retrained on the need for and strategies for timely ad-

ministration of birth doses of vaccines to babies born in

their facilities.

Innovative strategies such as the provision of single dose

hepatitis B vaccine vials such as Uniject can be used to

1

reach babies born outside of health care settings. This

Challenges of administering the birth dose of HBV in

Nigeria

would be within the framework of community care for

newborns and their mothers. Community health exten-

sion workers attached to Primary health care facilities

can be taught to use these single dose vaccines during

home visits to parturients.

For the birth dose of HBV to be effective in preventing

vertical transmission it is recommended that it be given

within 24 hours of birth. There are several challenges to

achieving the timeliness of delivery of the birth dose in

Nigeria. Firstly many Nigerian women do not receive

antena₈tal care. Antenatal care rate is 58% for at least one

Health education of mothers and their communities on

the need for timely administration of birth doses will

ensure that babies are brought for birth doses of vaccines

within 24 hours of delivery.

3

visit. In addition many health care providers do not

screen mothers for HBV antenatally. In one study only

Prenatal screening of mothers will ensure that mothers

know their status before delivery. For mothers who test

positive health workers will emphasize the need for

timely receipt of birth dose of the HBV vaccine. This

strategy will be akin to that of the prevention of mater-

nal to child transmission of HIV which has been found

to be successful in reducing new cases of childhood

HIV.

5

.9% of the mothers had been screened for hepatitis B

infect₄ion even though over 80% had received antenatal

3

care. Such screening can identify babies at risk of ver-

tical transmission who can then be offered the HBV

vaccine within 24hours of birth in addition to HBIG

given at a different site also within 24 hours of birth.

Another challenge is that most Nigerian women deliver

outside he₃a₈lth facilities. Institutional delivery rate is

only 35%. Babies born outside health facilities may

not be able to access health care facilities for immuniza-

tion within 24 hours. Many N₉ igerian infants initiate im-

Further research

Most studies on the effectiveness of the HBV vaccine in

prevention of perinatal transmission have had the birth

dose ₄o₁_,f₄₂ the vaccine given within 24 to 48 hours of

3

munization late. Sadoh et al reported that only 2 of 512

children presented for their first immunization in the

first day of life, In another recent study only 1.3% of the

studied infants₄presented within₄2₀4 hours of birth for

birth.

The Paediatric Association of Nigeria (PAN)

recommends that the b₃irth dose be given from birth up

4

to 2 weeks after birth. Studies are needed to determine

3

immunization. Olusanya et al also reported that

if such delayed birth doses are effective since if they are

not they may constitute a waste of resources.

3

1.8% of infants in Lagos were delayed beyond 3

months for the receipt of BCG, a₃₉vaccine that should be

received at birth. In Sadoh et al’s study they also noted

that despite the fact that many babies were born in

health facilities they did not receive the birth dose of

recommended immunizations before leaving the health

facility.

Cost effectiveness studies are also needed to determine

if the 4 dose regimen is cost effective in Nigeria. This

would also require the quantification of the contribution

of vertical transmission to chronic HBV carriage in Ni-

geria. This is in tandem with PAN recommendation that

there should be periodic review of the routine immuni-

zation schedule to enable its adaptation to changing dis-

ease and vaccine trends.

For the Nigerian hepatitis B immunization programme

to achieve a substantial decrease in HBV infections at-

tempts should be made to ensure that birth doses of the

vaccine are administered within 24 hours of birth. Nev-

ertheless, a late birth dose may be better than no birth

dose.

Conclusion

There is a significant potential for vertical and horizon-

tal transmission of the hepatitis B virus in Nigeria.

Therefore, administering the birth dose of the hepatitis B

1

08

vaccine is a good option for control of the hepatitis B

infection in Nigeria as it protects the baby as early as

possible from hepatitis B virus infection preventing

both, vertical and horizontal transmission. The major

challenge is in ensuring the timely administration of the

birth dose to every child regardless of whether they are

born in a health facility or not.

Author’s contribution

Sadoh AE, Sadoh WE: : Conceptualized work,

literature search and final draft.

Conflict of Interest: None

Funding: None

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