Case Study

MS, a 26-year-old woman, has arrived for her first prenatal visit. She is in the eighth week of her third pregnancy. Her previous pregnancies were uncomplicated with normal-term deliveries. Although she has never had any sexually transmitted diseases or symptoms of a sexually transmitted disease, she asks that you test her for everything, including herpes simplex virus (HSV) infection.

Case Study Questions

1. Which one of the following statements about serologic screening for genital HSV infection is correct?

• A. Asymptomatic women should be screened for HSV infection in the first trimester of pregnancy.

• B. All women of childbearing age should be screened for HSV infection.

• C. Asymptomatic women should not be screened for HSV infection during pregnancy.

• D. Sexually active adolescents should be screened for asymptomatic HSV infection.

• E. All asymptomatic adults should be screened for HSV infection.

2. One of MS’s past sexual partners was infected with HSV. Although MS has never had any herpetic lesions, she is worried that she could pass the infection to her baby and wonders what the treatment options are. Which one of the following statements about neonatal transmission and prevention of HSV infection is true?

• A. Antiviral treatment in pregnant women with a history of HSV infection leads to reduced rates of neonatal HSV infection.

• B. Pregnant women with recurrent HSV infection have the highest risk of maternal-infant HSV transmission.

• C. There is good evidence that cesarean delivery in women with active genital HSV lesions at the time of delivery decreases rates of neonatal HSV infection.

• D. Antiviral treatment for HSV infection in pregnant women has been linked to birth defects.

• E. In utero HSV transmission is rare.

3. Which of the following statements about symptoms and rates of HSV infection is/are correct?

• A. Twenty percent of the U.S. population aged 12 years and older has been infected with HSV-2.

• B. HSV infection caused by intrapartum transmission occurs in approximately one of every 100,000 deliveries.

• C. HSV viral shedding usually is accompanied by vesicular lesions.

• D. Encephalitis or disseminated disease secondary to neonatal HSV infection is associated with long-term morbidity and mortality.

Answers

1. The correct answer is C. The U.S. Preventive Services Task Force (USPSTF) recommends against routine serologic screening for HSV infection in asymptomatic pregnant women and asymptomatic adolescents and adults. The USPSTF found fair evidence that serologic screening of asymptomatic pregnant women does not reduce transmission of HSV to newborns. The USPSTF found no evidence that serologic screening of asymptomatic adolescents and adults improves health outcomes.

Serologic tests are used to detect previous infection with HSV in asymptomatic patients or to diagnose infection in a symptomatic patient when culture is not feasible or the clinical syndrome is unclear. The Western blot assay is considered the gold standard in serologic screening tests for genital HSV infection, with a sensitivity and specificity greater than 99 percent. Two serologic tests, the enzyme-linked immunosorbent assay and immunoblot, have a sensitivity and specificity comparable to the Western blot and can differentiate between HSV-1 and HSV-2 exposure.

Given the natural history of genital herpes, there is limited evidence to guide clinical intervention in asymptomatic persons with positive test results. False-positive results may lead to labeling and psychologic stress without any potential benefit to patients. Negative test results (both false-negative and true-negative) may provide false reassurance to continue high-risk sexual behaviors.

2. The correct answer is E. Congenital HSV infection caused by in utero transmission is rare (one per 100,000 deliveries) while neonatal HSV infection caused by intrapartum transmission is more common (one per 3,000 deliveries). Primary HSV infection during pregnancy presents the greatest risk for newborn transmission (33 percent transmission rate versus 3 percent for recurrent infections). However, pregnant women with primary infection initially are seronegative, limiting the usefulness of antibody testing.

There is limited evidence that antiviral therapy in women with a history of recurrent HSV infection and cesarean delivery in women with active HSV lesions decreases rates of neonatal herpes infection. Evidence is fair that antiviral therapy in late pregnancy can reduce HSV recurrence and viral shedding at delivery in women with recurrent HSV infection, but no evidence indicates that this therapy leads to reduced rates of neonatal infection. Antiviral treatments generally are well tolerated with mild harms. However, there is limited evidence of the safety of antiviral therapy in pregnant women and neonates. Harms of antiviral treatment may include drug hypersensitivity and renal impairment.

3. The correct answers are A and D. Genital HSV infection, commonly caused by HSV-2 and occasionally by HSV-1, is the most prevalent sexually transmitted infection in the United States. Studies show that one in five persons aged 12 years and older is seropositive for HSV-2, and the rate is even higher among adults and women. An estimated 1.6 million new HSV-2 infections occur annually. Neonatal HSV infection occurs more frequently than congenital HSV infection and is diagnosed in approximately one of every 3,000 deliveries in the United States.

Symptoms of genital HSV infection vary based on phase of infection. Primary infection manifests as tender vesicular lesions, dysuria, itching, lymphadenopathy, fever, malaise, and/or myalgia. Although viral shedding usually is asymptomatic, recurrent infections can manifest as localized lesions. Neonatal and congenital HSV infections can result in prematurity and low birth weight. Symptoms of HSV infection in neonates vary from mild localized disease to severe disseminated infection. Encephalitis and disseminated disease secondary to neonatal HSV infection are associated with long-term morbidity and mortality.