Structured Abstract
Please note: In 2003, the CTF updated its Grades of
Recommendations to include an "I Recommendation" for situations where
insufficient evidence exists to allow a recommendation to be made.
(Formerly, these situations were captured under a "C
Recommendation".) This change is not retroactive, and all
"C Recommendations" made prior to 2003 have not been
reevaluated in light of the new "I" recommendation grade. For a
discussion of these recommendation grades, please link to the 2003 article in
the Canadian Medical Association Journal here.
Prevention of Neonatal Herpes Simplex
Prepared by Elaine E.L. Wang, MD, CM, FRCPC, Department of Pediatrics,
University of Toronto
These recommendations were finalized by the Task Force in February
1989
Contents
Objective
To make recommendations for screening high-risk pregnant women in Canada
for genital herpes simplex virus (HSV) infection. This is an update of
the 1989 Canadian Task Force recommendations.
Burden
of Suffering
The clinical presentation in 70% of cases of neonatal herpes simplex is
skin involvement consisting of cutaneous vesicles. The clinical presentation
in 20% of cases is major systematic involvement, central nervous system
involvement, or both. Less than 10% of babies with neurologic disease
develop normally. The overall mortality rate among infants with untreated
infection is 65%. In 1981 the incidence of neonatal herpes was 12
cases per 100,000 live births. High-risk women are those with a history
of recurrent genital infection or active disease during the current pregnancy
and those with sexual partners who have proven HSV infection.
Options
Screening options are history-taking or detection of HSV antibodies by
microneutralization. Culture and clinical examination are also used. Treatment
options were not evaluated.
Outcomes
Risk of transmission, clinical disease and decision to deliver vaginally
or by cesarean section based on screening results.
Evidence
MEDLINE was searched to 1993 using the keywords herpes simplex, pregnancy
and infant, newborn.
Recommendations were graded as:
|
A
|
Good evidence to support the recommendation that the condition
be specifically considered in a PHE. |
|
B
|
Fair evidence to support the recommendation that the condition
be specifically considered in a PHE. |
|
C
|
Poor evidence regarding inclusion or exclusion of the condition
in a PHE, but recommendations may be made on other grounds. |
|
D
|
Fair evidence to support the recommendation that the condition
be specifically excluded from consideration in a PHE. |
|
E
|
Good evidence to support the recommendation that the condition
be specifically excluded from consideration in a PHE. |
Quality of evidence was rated according to 5 levels:
|
I
|
Evidence from at least 1 properly randomized controlled
trial (RCT). |
|
II-1
|
Evidence from well-designed controlled trials without randomization. |
|
II-2
|
Evidence from well-designed cohort or case-control analytic
studies, preferably from more than 1 centre or research group. |
|
II-3
|
Evidence from comparisons between times or places with
or without the intervention. Dramatic results in uncontrolled experiments
could also be included here. |
|
III
|
Opinions of respected authorities, based on clinical experience,
descriptive studies or reports of expert committees. |
Values
The 13-member Task Force of experts in family medicine, geriatric medicine,
pediatrics, psychiatry and epidemiology used an evidence-based method for
evaluating the effectiveness of preventive health care interventions. Recommendations
were not based on cost-effectiveness of options. Patient preferences were
not discussed.
Background papers providing critical appraisal of the evidence and tentative
recommendations prepared by the chapter author were pre-circulated to the
members. Evidence for this topic was presented and deliberated upon in
1- to 2-day meetings, 2 to 3 times per year from January 1993 to June 1993.
Consensus was reached on final recommendations.
Benefits,
Harms, and Costs
History taking to identify women who are at high risk of transmission is
unreliable. In a study of 184 cases of neonatal HSV infection only 22%
of mothers reported having had a positive history of genital HSV infection
and only 9% had genital lesions at delivery. Patients are often unaware
of their previous active infections.
Although it is accurate, the cervical smear culture takes 3 days to
complete and therefore is not useful for making decisions for women in
labour. In these cases, the penultimate culture result is used, but
this has very low predictive validity for the presence of infection at
the time of delivery.
Decision analysis of 9 different strategies for the prevention of neonatal
HSV infection (involving physical examination, culture, and antigen testing
for all or high-risk women) showed physical examination during labour to
be the optimal strategy given the goal of minimizing the ratio of excess
cesarean sections to cases of neonatal HSV infections. Approximately 30
excess cesarean sections would be done for each case prevented. Strategies
involving screening of high-risk women would require 36 to 178 extra cesarean
sections per case averted.
Economic analysis showed that the cost for each case of neonatal HSV
infection prevented would be U.S. $37 million. A U. S. national screening
program would prevent 1.8 cases/y.
Recommendations
Recommendation grade [A, B, C, D, E] and level of evidence
[I, II-1, II-2, II-3, III] are indicated after each recommendation. Citations
in support of individual recommendations are identified in the guideline
text.
-
Fair evidence exists to exclude weekly screening for herpes simplex virus
from the routine prenatal care of high risk women. [D,
II-2]. (High risk is defined as women with
positive test results, history of recurrent herpes simplex, active disease
during current pregnancy, and those with sexual partners who have genital
herpes simplex.)
-
Poor evidence exists to include or exclude cesarean section for delivery
of pregnant women with positive findings of herpes simplex virus at clinical
examination [C, III].
Validation
This report was externally peer reviewed. The Committee on Infectious Disease
of the American Academy of Pediatrics no longer supports screening. The
Infectious Diseases and Immunization Committee of the Canadian Pediatric
Society recommended that history and physical examination, but not culture,
be used for screening, and that all infants with mothers who have genital
lesions or a history of infections should be examined and followed. The
1989 U.S. Preventive Services Task Force recommended screening pregnant
women with active lesions for genital HSV. The 1992 Infectious Disease
Society of America recommended against serial viral cultures for women
with recurrent infections and analysis of apparent lesions, and recommended
for provision of education and reassurance for women with histories of
genital herpes and cesarean section and culture before, or as soon as possible
after, rupture of membranes for women with active genital herpes during
labour.
Sponsors
The Canadian Task Force on Preventive Health Care
developed this guideline with funding from Health Canada.
Selected
References
Source Document
Other
-
Canadian Task Force on the Periodic Health Examination: The periodic health
examination, 1989 update part 4, Intrapartum electronic fetal monitoring
and prevention of neonatal herpes. Can Med Assoc J. 1989;141:1233-40.
Link to Full Text of this
review
Link to Summary Table of Recommendations of this review
Link to Selected References list of this review
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