Herpes Simplex Virus Type-2 Seroprevalence and Risk Factors Among Pregnant Women at Etoudi Marie Reine Medical Centre, Yaoundé-Cameroon

Introduction: Herpes simplex virus type 2 (HSV-2) is a major cause of genital ulcer disease globally. In pregnancy, genital ulcers are linked to serious outcomes like spontaneous abortion, preterm delivery, and neonatal herpes. However, there is limited data on HSV-2 seroprevalence in Cameroon. This study aimed to assess HSV-2 seroprevalence and its risk factors among pregnant women at Etoudi Marie Reine Medical Centre (EMRC), Yaoundé-Cameroon.

Methods: A cross-sectional study was conducted in 90 pregnant women attending EMRC of Yaoundé, Cameroon, from April 17 to May 24, 2024. Blood samples were collected to detect anti-HSV-2 antibodies (IgM and IgG) using the Enzyme-Linked Immunosorbent Assay (ELISA). Data collected with a structured questionnaire were entered into Microsoft Excel version 2016 and analysed using Epi-info version 7.1.2.0. A p-value of <0.005 was considered statistically significant.

Results: The mean age of the study participants was 29 years, with a standard deviation of ±5.66, ranging from 15 to 41 years. Of the 90 pregnant women enrolled in the study, the overall carriage rate of antibodies (IgM and IgG) was 55.5%. The seropositivity rates for IgM) and IgG) were 1.1% (95% CI: 0.03%-6.04%, n = 1) and 54.4% (95% CI: 43.60%-64.98%, n = 49), respectively. The IgM seropositivity rate was only observed in the second trimester at 2.04% (1/49) and among women with no history of abortion at 1.41% (1/71). The IgG seropositivity rate was significantly associated with age group (X² = 8.89; p = 0.01), the age group of first pregnancy (X² = 8.15; p = 0.02), and alcohol consumption (X² = 4.26; p = 0.03). Furthermore, the IgG seropositivity rate was highest in women during their first trimester, with 41.67% (10/24), and among women who had experienced at least one abortion with 68.48% (13/19).

Conclusion: This study revealed a significant prevalence of HSV-2 antibodies among pregnant women at EMRC in Yaoundé, Cameroon, with IgG seropositivity notably higher than IgM. The findings highlight the importance of screening and monitoring HSV-2 among pregnant women, particularly those in their first trimester and those with a history of abortion.

Introduction

Herpes simplex virus (HSV) is an enveloped virus with a double-stranded DNA genome and an icosahedral capsid structure [1]. It is classified within the Orthoherpesviridae family, subfamily Alphaherpesvirinae, and genus Simplexvirus [1], [2]. Both HSV types (HSV-1 and HSV-2) can establish lifelong infections by residing in the host’s nervous system, remaining dormant, and reactivating under conditions like stress, illness, or immune suppression [1]. HSV-1 is typically associated with oral herpes, causing cold sores around the mouth, while HSV-2 primarily causes genital herpes [2] [3]. An estimated 491.5 million individuals 15–49 years of age worldwide were living with HSV-2 infection, with more women than men being infected [4]. HSV-2 infection is a chronic, incurable, and globally prevalent sexually transmitted infection (STI) known for persistent reactivation and frequent shedding [5], [6]. HSV-2 infection occurs mainly in the genital mucosa, and it is associated with risk factors for certain sexually transmitted diseases (STDs) such as AIDS [7], [8]. HSV-2 can also be transmitted from mother to infant during delivery, a process termed vertical transmission, which can result in neonatal herpes [4]. This severe infection poses significant health risks for newborns, including high morbidity and mortality rates due to the virus’s ability to disseminate across multiple organ systems [3]. In neonates, this infection can spread to vital organs, including the liver, lungs, and central nervous system, potentially causing severe complications like neurological deficits, seizures, or death if untreated [7]. The risks are heightened during primary maternal infection late in pregnancy, as maternal antibodies may not fully develop to protect the infant [3], [4], [7].

A study conducted in the Republic of Haiti reported an HSV-2 prevalence of 31.4%. Among HSV-2-positive pregnant women, the prevalence of HIV was five times higher than among HSV-2-negative women, at 4.8% vs. 0.9%, respectively [9]. In Nigeria, Onu et al. [10] found a high HSV-2 IgG antibodies of 56.2% in patients with HIV, and this seroprevalence was more recorded in females (57.9%, 92/159). In Cameroon, a study conducted among women and their Newborns in Douala shows an HSV-2 prevalence of 90% and 74.7% in mothers and their babies, respectively [11]. The prevalence of HSV-2 antibodies among Adolescents and adults in Northern Cameroon was found to be 37.1% [12]. All these studies have shown a high prevalence of HSV-2 in various population groups, highlighting that HSV-2 remains a significant public health issue, especially in resource-limited settings such as Cameroon. Moreover, information is lacking about the prevalence of HSV-2 infection among pregnant women in Cameroon. This study aims to determine the HSV-2 seroprevalence and risk factors among pregnant women at the EMRC in Yaoundé, Cameroon.

Materials and Methods

Study Design and Population

This cross-sectional study involved 90 pregnant women attending the EMRC in Yaoundé, Cameroon, between April 17 and May 24, 2024. Participants were recruited based on eligibility criteria that included informed consent and regular antenatal visits to the clinic. The aim was to detect HSV-2 antibodies and analyse associated risk factors. Each participant completed a structured questionnaire that included quantitative and qualitative variables.

Ethical Considerations

Ethical clearance for this current study was obtained from the Centre Regional Ethics Committee for Human Health Research (CE N°298/CRERSHC/2024, dated May 14, 2024). All pregnant women voluntarily agreed to participate by reading the information note and signing the informed consent form. To ensure confidentiality, each participant was assigned a unique identification code, which was used throughout the study to protect their privacy.

Sampling Method and Sample Size Determination

The sampling technique used in this study was non-probabilistic, and the sample size was determined using the Cochran formula [13]:

n=Z2p(1−p)e2

where:

z = the standard deviation of 1.96 (95% confidence interval),

p = estimated proportion of HSV-2 IgM (p = 2.1%) among pregnant women in India [14],

e = allowable error (5%).

Blood Sample Collection and Analysis

Under aseptic conditions, 5 ml of venous blood was collected into a dry tube via venipuncture. The samples, along with the consent forms, were immediately transported to the central laboratory. The blood specimens were centrifuged at 3000 rpm for 5 minutes to separate the sera, which were then frozen until serological testing. Enzyme-Linked Immunosorbent Assay (ELISA) was performed to detect IgM (DiaSino Laboratories Co., Ltd., China, REF: DS180610, Lot No: 00230330, manufactured on 2023/03/30, expiring 2024/09/29) and IgG (DiaSino Laboratories Co., Ltd., China, REF: DS180609, Lot No: 00230330, same manufacture and expiration dates) antibodies against HSV-2, following the manufacturer’s guidelines.

Statistical Analysis

Data were entered into Microsoft Excel 2016, organized, and transferred to Epi-Info version 7 for statistical analysis. Descriptive statistics included absolute and relative frequencies, variable distribution (quantitative and qualitative), average age, standard deviation, and median age. The prevalence of each HSV-2 biomarker (IgM and IgG) was calculated by dividing the effective count for each modality by the total population, multiplying by 100, and expressing the results as percentages. Proportions of variables were compared using chi-square and Fisher’s exact tests. A p-value of less than 0.05 (p < 0.05) was considered statistically significant, indicating meaningful differences between groups.

Results

Distribution of Sociodemographic Characteristics of the Study Population

90 pregnant women participated in this study, with ages ranging from 15 to 41 years, and the mean age was 29 years (SD = 5.66). Most of the participants were between 25 and 34 years old (53.33%, n = 48), single (68.9%, n = 62), had a secondary school education (50.0%, n = 45), lived in urban areas (97.8%, n = 88), identified as Christian (93.3%, n = 84), Labourer or Hand worker (43.3%, n = 39) (see Table I).

Table I. Distribution of Sociodemographic Characteristics of the Study Population

Variables	Total (N = 90)	Percentage (%)
Age group (in years)
15–24	24	26.7
25–34	48	53.3
35–41	18	20.0
Marital status
Married	28	31.1
Single	62	68.9
Education level
No formal education	3	3.3
Primary	3	3.3
Secondary	45	50.0
Higher	39	43.4
Zone
Rural	2	2.2
Urban	88	97.8
Religion
Christian	84	93.3
Other	6	6.7
Occupation
Employee	17	18.9
Informal sector	16	17.8
Labourer or hand worker	39	43.3
Student	18	20.0

Distribution of Behaviour Risk among Study Participants

Table II shows that 81.1% (n = 73) of pregnant women had their first intercourse at an age ≥17 years; the age ranges from 20–24 recorded the highest number of pregnant women with 37.8 % (n = 34); about 54 % (49/90) had a second-semester pregnancy and at the same time, no abortion case was recorded among 78.9% (71/90). 61.1% (55/90) of these pregnant women were not using condoms during intercourse, while 53.3 % (48/90) of them were used to alcohol consumption.

Table II. Distribution of Behaviour Risk among Study Participants

Variables	Frequency (N = 90)	Percentage
Age of first intercourse (in years)
<17	17	18.9
≥17	73	81.1
Age of first pregnancy(in years)
<20	25	27.8
20–24	34	37.8
≥25	31	34.4
Age of pregnancy
First trimester	24	26.7
Second trimester	49	54.4
Third trimester	17	18.9
Number of abortion
Zero	71	78,9
≥1	19	21.1
Condoms use
Never	55	61.1
Always	35	38.9
Alcohol consumption
No	42	46.7
Yes	48	53.3

C-Distribution of Antibodies Anti-HSV-2 (IgM and IgG) among the Participants

Of the 90 pregnant women enrolled in the study, the overall carriage rate of antibodies (IgM and IgG) was 55.5%. The seropositivity rates for IgM and IgG were 1.1% (95% CI: 0.03%–6.04%, n = 1) and 54.4% (95% CI: 43.60%–64.98%, n = 49), respectively (Fig. 1).

Fig. 1. Distribution of the antibodies anti-HSV-2 (IgM and IgG) among participants.

D-Distribution of Sociodemographic Characteristics According to Antibodies Anti-HSV-2

Table III below shows that the only case of IgM seropositivity reported in this study was in pregnant women aged 25–34 (2.08%), married (3.57%), higher education (2.56%), urban area (1.1%), Christian (1.19%), informal sector (6.25%) with no significant difference. The IgG seropositivity rate was significantly associated with the age group (X² = 8.89; p = 0.01), with high proportions recorded in the 35–41 (83.33%) and 25–34 (52.08%) age groups. In addition, the IgG rate was high among pregnant women who were married (64.29%), in primary school (100%), in urban areas (54.55%), of other religions (66.67%) and in the informal sector (68.75%), with no significant difference.

Table III. Distribution of Sociodemographic Characteristics by Antibodies anti-HSV-2 (IgM and IgG)

Variables	Anti-HSV-2 IgM		X2 (p-value)	Anti-HSV-2 IgG		X2 (p-value)
	IgM + 1 (%)	IgM − 89 (%)		IgG + 49 (%)	IgG − 41 (%)
Age (in years)			0.88 (0.82)			8.89 (0.01)
15–24	0	24 (100)		9 (37.5)	15 (62.5)
25–34	1 (2.08)	47 (97.92)		25 (52.08)	23 (47.92)
35–41	0	18 (100)		15 (83.33)	3 (16.67)
Marital status			2.23 (0.13)			1.58 (0.20)
Married	1 (3.57)	27 (96.43)		18 (64.29)	10 (35.71)
Single	0	62 (100)		31 (50.00)	31 (50.00)
Education level			1.32 (0.72)			1.08 (0.77)
No formal education	0	3 (100)		2 (66.67)	1 (33.33)
Primary	0	3 (100)		3 (100)	0
Secondary	0	45 (100)		24 (53.33)	21 (46.67)
Higher	1 (2.56)	38 (97.44)		20 (51.28)	19 (48.72)
Zone			0.02 (0.87)			0.35 (0.55)
Rural	0	2 (100)		1 (50.00)	1 (50.00)
Urban	1 (1.1)	87 (98.9)		48 (54.55)	40 (45.45)
Religion			2.51 (0.11)			0.04 (0.84)
Christian	1 (1.19)	83 (98.81)		45 (53.57)	39 (46.43)
Other	0	6 (100)		4 (66.67)	2 (33.33)
Occupation			1.57 (0.66)			3.77 (0.29)
Employee	0	17 (100)		8 (47.06)	9 (54.94)
Informal sector	1 (6.25)	15 (93.75)		11 (68.75)	5 (31.25)
Labourer/Hand worker	0	39 (100)		23 (58.97)	16 (41.03)
Student	0	18 (100)		7 (38.89)	11 (61.11)

D-Distribution of Behaviors According to Antibodies Anti-HSV-2 (IgM and IgG)

Table IV shows that the only cases of IgM seropositivity were observed in pregnant women having their first sexual intercourse (age ≥17 years) with 1.37%, with the age of first pregnancy of 20–24 years (2.94%), the second trimester of pregnancy (2.04%), without abortion (1.41%), who did not use a condom during sexual intercourse (1.82%), and who consumed alcohol (2.1%). According to the IgG seropositivity rate, an association was found between the age group of the first pregnancy (X² = 8.15; p = 0.02) and alcohol consumption (X² = 4.26; p = 0.03). In addition, the IgG seropositivity rate was high in pregnant women having their first sexual intercourse (age ≥17 years) with 57.53%, second trimester of pregnancy (61.22%), abortion ≥1 (68.42%), non-use of condoms during sexual intercourse (58.18%), with no significant difference.

Table IV. Distribution of Behaviors by Antibodies Anti-HSV-2 (IgM and IgG)

Variables	Anti-HSV-2 IgM		X2 (p-value)	Anti-HSV-2 IgG		X2 (p-value)
	IgM + 1 (%)	IgM − 89 (%)		IgG + 49 (%)	IgG − 41 (%)
Age of first intercourse (in years)			0.64 (0.42)			1.48 (0.22)
<17	0	17 (100)		7 (41.18)	10 (58.82)
≥17	1 (1.37)	72 (98.63)		42 (57.53)	31 (42.47)
Age of first pregnancy (in years)			0.43 (0.86)			8.15 (0.02)
<20	0	25 (100)		17 (68.00)	8 (32.00)
20–24	1 (2.94)	33 (97.06)		12 (35.29)	22 (64.71)
≥25	0	31 (100)		20 (64.52)	11 (35.48)
Age of pregnancy			0.72 (0.69)			2.50 (0.29)
First trimester	0	24 (100)		10 (41.67)	14 (58.33)
Second trimester	1 (2.04)	48 (97.96)		30 (61.22)	19 (38.78)
Third trimester	0	17 (100)		09 (52.94)	8 (47.06)
Number of abortions			0.50 (0.47)			1.89 (0.16)
Zero	1 (1.41)	70 (98.59)		36 (50.70)	35 (49.30)
≥1	0	19 (100)		13 (68.42)	6 (31.58)
Condoms use			0.05 (0.83)			0.79 (0.37)
Never	1 (1.82)	54 (98.18)		32 (58.18)	23 (41.82)
Always	0	35 (100)		17 (48.47)	18 (51.43)
Alcohol consumption			0.005 (0.94)			4.26 (0.03)
No	0	42 (100)		24 (57.10)	18 (42.90)
Yes	1 (2.1)	47 (97.9)		17 (35.40)	31 (64.60)

Discussion

We conducted this study to determine the HSV-2 seroprevalence and its associated risk factors among pregnant women. Our results revealed an overall HSV-2 seroprevalence of 55.5%, a high prevalence that underscores the significant burden of this infection in this population. Comparatively, a study conducted in Nigeria by Iche et al. [15] reported a global HSV-2 seroprevalence of 44.3%, which is considerably lower than the prevalence observed in our study. Furthermore, evidence of TORCH infections was reported in 66.7% of women in a study conducted by Tiwari et al. [16], with HSV infections accounting for the highest proportion (30.10%). This indicates the substantial role HSV-2 plays in the spectrum of infections affecting maternal and neonatal health, particularly in resource-limited settings. The higher seroprevalence of HSV-2 in developing regions is further corroborated by data from sub-Saharan Africa, where prevalence rates range from 10% to 50% in men and 30% to 80% in women [17].

In this study, HSV-2 IgM seroprevalence was 1.1% (95% CI: 0.03%–6.04%, n = 1). The presence of IgM antibodies in the blood may indicate either a recent infection or one that is in the process of resolving. This proportion is found to be relatively lower than that observed in India by Amar et al. [14], who found an IgM seropositivity rate of 2.1%. However, this is very different from that observed by Ahmed et al. [18], who reported an IgM seropositivity rate of 38% in their study. No significant difference was found between IgM seropositivity and risk factors. However, the only case of IgM seropositivity reported in our study was in pregnant women aged 25–34 years, in the second trimester of pregnancy (2.04%) and those with no abortion (1.41%). Our results are contrary to those observed in the study conducted by Ahmed et al. [18], who found a significant association between the rate of IgM seropositivity and the age distribution group (p = 0.001). In addition, his study showed that the IgM seropositivity rate was higher during the first trimester of pregnancy (34.2%) and in pregnant women with a history of abortion (20.7%). The study by Amar et al. [14] showed that IgM seropositivity was highest in the first trimester, followed by the third and second trimesters with no significant difference. Furthermore, no difference was found between IgM seropositivity and the age groups of pregnant women [14]. This difference could be explained by the small size of our study and the sampling technique used.

The overall seropositivity rate for IgG in this study was 54.4% (95% CI: 43.60%–64.98%, n = 49). This high IgG rate means that pregnant women in this locality have been in contact with the virus. This result corroborates several studies conducted worldwide, which have also found high IgG seropositivity rates in pregnant women [14], [18]–[20]. This study showed a significant association between the rate of IgG seropositivity and the age group of women, with high proportions in those aged 35–41. (X² + 8.89 p = 0.01). This result is contrary to that observed by Ahmed et al. [18], who reported a higher rate of IgG seropositivity in pregnant women aged between 15 and 24. In our study, the IgG seropositivity rate was high in pregnant women in the second trimester (61.22%) and third trimester (52.94) of pregnancy. Similar results were reported by Anaedobe et al. [19] and Amar et al. [14], who found that IgG seropositivity was higher in the third and second trimester of pregnancy. Our result is contrary to that found by Ahmed et al. [18], who showed that the seropositivity rate for anti-HSV-2 IgG was higher during the first trimester of pregnancy. This difference could be explained by the sampling technique used. In this study, the IgG seropositivity rate was higher in pregnant women with a history of abortion (68.42%), with no significant difference. By comparison, our result is contrary to that found by Ahmed et al. [18], who observed a higher IgG rate (54.3%) in women with no history of abortion.

In this study, no significant association was found between IgM/IgG seropositivity rate, age of first sexual intercourse, and condom use during sexual intercourse. Furthermore, no association was found between the age of the first pregnancy and IgM seropositivity. However, a significant association was found between IgG seropositivity, age at first pregnancy (X² = 8.15; p = 0.02), and alcohol consumption (X² = 4.26; p = 0.03). It should be noted that HSV-2 infection, like the majority of sexually transmitted infections (STIs), is systematically influenced by certain behaviours, most of which are characteristic of unfavourable socio-economic conditions [21], [22]. It is also interesting to note that alcohol consumption mainly affects sensation-seekers. [23], [24]. It could therefore influence the behaviour of these individuals to engage in unprotected sexual activity. A study conducted in Cape Town, South Africa, found an association between HIV infection and alcohol consumption [24]. Our results are contrary to those of Beydoun et al. [25], a study conducted among adults in the USA which found no association between alcohol consumption and HSV infection.

Limitations

The present study recorded some limitations. The small size of our sample does not allow us to generalise the results of this study. This is justified by the scarcity of women attending antenatal clinics, the limited resources of the investigators, and the lack of funding. The nature of the study (cross-sectional study) did not allow us to carry out an in-depth analysis of the information collected from the pregnant women, in particular self-reported risk behaviour.

Conclusion

The study revealed a significant prevalence of HSV-2 antibodies among pregnant women at EMRC in Yaoundé, Cameroon, with IgG seropositivity notably higher than IgM. The findings highlight the importance of screening and monitoring HSV-2 among pregnant women, particularly those in their first trimester and those with a history of abortion, as they exhibited higher seroprevalence rates. Despite the relatively low prevalence of recent infections (IgM), the presence of IgG antibodies indicates ongoing exposure and potential risks of transmission to the foetus.

Recommendations

The findings of this study revealed a significant prevalence of HSV-2 antibodies among pregnant women at EMRC in Yaoundé, Cameroon. This underscores the need for targeted health campaigns to raise awareness, provide education, and offer preventive measures against genital herpes in order to reduce its impact on maternal and neonatal health. Further research and intervention programs are essential to address the burden of HSV-2 in resource-limited settings.