POLICY STATEMENT
The Institute of Medicine has called for better health outcomes with specific attention paid to VPDs, with one approach being incorporation of immunizations into routine obstetric and gynecologic practice. Nurse-midwives are uniquely positioned to vaccinate women of all ages and provide more general midwifery care to women than either family practice or internal medicine providers.
BLOOD BORNE PATHOGEN
EXPOSURE CATEGORY: I (Involves exposure to blood, body fluids, or tissues) FUNCTION: Care of Clients
EQUIPMENT:
1. Laboratory supplies and equipment POINTS OF EMPHASIS:
During the 20th century, the average life span of U.S. residents lengthened by more than 30 years, 25 of which are directly attributable to advances in biomedical science and public health. Reduction and eradication of vaccine-preventable diseases (VPDs) through immunization is a major contributor to this improvement. Smallpox and poliomyelitis have been eliminated in the United States, and cases of measles, mumps, rubella, tetanus, and diphtheria have been decreased by 95 to 99%.
In 2011, the Centers for Disease Control and Prevention (CDC) identified the reduction in VPDs as one of the greatest achievements of the previous decade. Several new vaccines were introduced during that time including rotavirus, quadrivalent meningococcal conjugate, herpes zoster, human papillomavirus, pneumococcal conjugate and adult tetanus, diptheria, acellular pertussis (Tdap).
Despite the impact of immunizations and its public health priority by the CDC, vaccine coverage among U.S. adults remains below CDC goals. More than 50,000 U.S. adults continue to die each year from VPDs and their associated complications. Influenza causes up to 49,000 annual deaths, and pneumococcal disease is responsible for over 175,000 hospitalizations due to pneumonia, bacteremia, and meningitis. Additionally, cervical cancer caused by the human papilloma virus is responsible for the deaths of approximately 4000 adult women annually.
Pregnant women are at significant risk for influenza-related morbidity and mortality. Influenza has been associated with pre-term birth and fetal growth restriction. Perinatal transmission of rubella and varicella are associated with complex congenital anomalies, and perinatally acquired HB is highly associated with lifelong disease. In addition to preventing maternal and congenital disease, maternal immunization can also provide direct infant protection via passive immunity. Transplacental transfer of immunoglobulin G antibodies from the vaccinated mother provides immunity for infants up to 5 to 6 months of life. This is particularly relevant for for infant protection against influenza and pertussis, given that no influenza vaccine is licensed for use prior to 6 months of age and protection against pertussis following infant immunization is not established until after 6 months of age following at least two to three Tdap vaccine doses.
The successes of previous and ongoing vaccination efforts among obstetrical providers are demonstrated by the near eradication of congenital rubella and Rhesus (Rh) disease in the United States through antenatal surveillance and antepartum/postpartum immunization as well as widespread administration of H1N1 vaccine to pregnant women during the 2009 pandemic. Nurse-midwives are positioned to provide even greater protection for both mothers and their infants against VPDs via vaccination during pregnancy and recommends 10 vaccines covering 14 VPDs, of which six vaccines are recommended during pregnant and two during the postpartum period, depending upon individual risk factors.
Classification of Vaccines
Vaccines are broadly classified as live attenuated or inactivated vaccines. Live attenuated vaccines are made from laboratory manipulation of disease-causing pathogens via multiple rounds of tissue culture for selection of less virulent strains, mutagenesis, or targeted gene deletions required for virulence. The vaccine contains very-low-virulent pathogens that replicate at a very slow rate in the vaccinated individual and stimulate an immune response. Although attenuated vaccines usually do not cause disease, any resulting illness that might occur in uncommon cases is typically much milder than the natural disease and is considered an adverse reaction. The immune response to live vaccines in healthy individuals is typically the same as would occur after natural pathogen exposure.
Immunocompromised individuals can have severe or fatal reactions due to unregulated replication of the vaccine pathogen and thus cannot receive such vaccines. Live attenuated vaccines are contraindicated during pregnancy based on the theoretical risk of perinatal disease transmission (e.g., congenital rubella or varicella).
Inactivated vaccines are manufactured by pathogen culture followed by inactivation with heat or chemicals. The resultant vaccine cannot replicate or cause disease as it contains no living or infectious particles. The immune response generated by inactivated vaccines is typically humoral waning antibody levels and immunity over time. Therefore inactivated vaccines require multiple and/or booster doses to maintain protective antibody levels. Inactivated vaccines include whole-cell viral or bacterial, fractional subunits or (T-cell independent) or conjugated (T-cell dependent). Recombinant vaccines, which can be live attenuated or inactivated, contain virus or bacteria that have been genetically engineered.
Tetanus, Diphtheria, and Pertussis
Children in the U.S. are routinely immunized against Tdap. Tetanus is caused by Clostridium tetani and results in prolonged muscular contraction due to tetanospasmin neurotoxin. Diphtheria is an upper respiratory infection caused by Corynebacterium diphtheriae. Decennial and exposure-related booster dosing of tetanus-diphtheria vaccine in adolescence and adulthood has resulted in the near eradication of both conditions in the United States. Pertussis, or whooping cough, is a respiratory infection caused by Bordetella pertussis that results in prolonged cough with a deep inspiratory “whoop” in classic cases. First introduced in the 1940s, pertussis-containing vaccines were highly effective in reducing disease, with reported pertussis cases decreasing from 200,000 cases in 1934 to a nadir of 1,010 cases in 1976. After many years of low, stable disease rates, annual pertussis incidence began to steadily rise, with about 29,000 cases reported from 1997 to 2000. Adolescents and adults have had the highest incremental increase in disease incidence, most likely due to waning immunity following primary childhood vaccination series and lack of booster dosing against pertussis. However, infants <12 months of age have the highest overall incidence and disease-related morbidity and mortality given that the primary Tdap 5-vaccine series is not completed until 4 to 5 years of age.
Cocooning, the practice of vaccinating persons in close contact with infants such as parents, grandparents, and siblings, is one method of reducing communicable infectious diseases in infants. CDC’s Advisory Committee on Immunization Practices recommended a Tdap vaccine cocooning strategy in 2005, with specific attention paid to vaccination of new mothers in the immediate postpartum period. Cocooning has had limited success due to low implementation of Tdap vaccination programs in the U.S. hospitals and low coverage of fathers and other close contacts. In 2011, CDC revised the recommendations for adult Tdap vaccination to include maternal immunization during pregnancy. Although based primarily on observational data, there has been no safety signal or concern for adverse events following Tdap vaccination during pregnancy. Due to theoretical risks of teratogenesis with first-trimester exposure, vaccination is recommended after 20 weeks’ gestation. Passive infant immunization has been documented following maternal immunization. Two recently completed randomized trials of maternal Tdap immunization should provide further data as well as identify correlates and duration of protection in the neonate. Hepatitis A
Hepatitis A virus (HAV) is an RNA picornavirus transmitted via fecal-oral route, primarily from close contact with infected persons and contaminated food and drinks. HAV causes an acute liver infection associated with fever, malaise, nausea, abdominal pain, and jaundice but does not lead to a chronic carrier state. In addition to the recommendation for universal vaccination between 12 and 23 months of age, CDC recommends vaccination of adults at high risk of HAV exposure. High-risk groups include those traveling to areas with high to intermediatee endemicity, men having sex with men, occupational exposure to infected persons or biospecimens, and people with clotting-factor deficiencies receiving clostting-factor concentrates. Although there is insufficient evidence to declare safety for use during pregnancy, the current vaccine is inactivated with no live virus components and therefore
unlikely to cause infection or harm to the mother or fetus. CDC recommends hepatitis A vaccination during pregnancy when the risk of infection outweighs the potential risk of vaccination. Further study into the use of the hepatitis A vaccine in pregnancy is warranted to establish efficacy and safety.
Hepatitis B
HB virus is a DNA virus transmitted via infected blood and bodily fluids that causes acute liver inflammation, vomiting, and jaundice. Long-term consequences of chronic HB infection include cirrhosis, hepatocellular carcinoma, liver failure and death. The HB vaccine is manufactured by recombinant DNA technology based on the hepatitis B surface antigen envelope protein (HBsAg). A three-vaccine series in adults is highly effective for disease prevention, providing a protective antibody response in greater than 90% of individuals.
The primary concern for HB during pregnancy is the risk of vertical transmission, as perinatal infection is associated with the highest risk of developing chronic disease. Women are routinely screened for HBsAg status as postexposure neonatal prophylaxis with HB immunoglobulin and initiation of HB vaccine series in the first hours of life is an effective strategy for preventing vertical transmission. Perinatal transmission most commonly occurs at the time of delivery; however, in utero vertical transmission can and dose occur, most likely among women with acute HP infection during the third trimester. Thus, HB vaccination remains the best overall preventive measure against HB infection, including in pregnancy. Pregnant women who have not been vaccinated previously and are at high risk of acquiring infection should be vaccinated during pregnancy with the three-dose HB vaccine series with consideration for rescreening for HBsAg at the time of delivery. Although limited, safety data have not demonstrated any
association between HB vaccination and adverse pregnancy outcomes, which is not unexpected given the vaccine is a recombinant inactivated product that does not contain live virus. Beginning in the late 1990s, states began implementing HB vaccine mandates for children in daycare, elementary school, and middle school, in which proof of vaccination or immunity must be provided prior to school enrollment, with the goal of eventual universal coverage. The earliest mandates went into effect in 1995 with some as recent as 2009, and three states are without any mandates to date (Alabama, Montana, South Dakota). Universal HB vaccination of children born and/or educated in the United States will likely result in near-complete coverage of women of childbearing age in the future.
Pneumococcal Disease
Streptococcus pneumonia (pneumococcus) is a Gram-positive bacterium responsible for causing serious illnesses including pneumonia, meningitis, bacteremia, and acute otitis media. In 2005, the WHO estimated that over 1 million people die from pneumococcal disease each year, with the majority of deaths occurring in children under the age of 5 years. Medical risk factors include chronic heart disease, chronic lung disease such as asthma, diabetes mellitus, cigarette smoking, alcoholism, chronic liver disease, cerebrospinal fluid leaks, cochlear implants,
congenital or acquired immunodeficiencies, diseases requiring immuno-suppressant therapy, sickle cell disease and other hemoglobinopathies, and functional or anatomic asplenia.
CDC has deemed there is insufficient evidence to make a recommendation regarding routine administration of PCV13 and PPSV23 during pregnancy. Third-trimester vaccination has been studied by multiple groups and has not been associated with safety concerns or adverse outcomes. Maternal PPSV23 vaccination does lead to increased neonatal antibody titers at delivery compared with neonates of unimmunized mothers; however, it is unclear if passive immunization of the neonate leads to disease protection. However, vaccination during pregnancy results in protective maternal antibody titers for up to 12 months postpartum. Of note, the majority of date on pneumococcal vaccination during pregnancy has been collected in developing countries, which have different patterns of exposure and colonization than the United States. PPSV23 is currently recommended for pregnant women who have a medical risk factor, which may affect a fair number of women, particularly those in maternal-fetal medicine practices who often have high-risk medical conditions.
Meningococcal Disease
Neisseria meningidis is an encapsulated bacterium that causes 1,400 to 2,800 cases of meningitis and sepsis in the United States each year, with highest disease incidence in infants. Adolescents and adults at high risk of infection include college students living in dormatories, military recruits, persons with terminal compliment component deficiencies, persons with functional or anatomic asplenia, researchers with routine exposure to N. meningitidis isolates, and persons residing in areas where N. meningitidis is hyperendemic or currently experiencing an epidemic. CDC recommends the tetravalent meningocoocal conjugate vaccine (MCV4) for high-risk individuals between the
ages of 11 and 55 years. A tetravalent meningococcal polysaccharide vaccine (MPSV4) is also available but does not conver long term immunity. Therefore, MPSV4 is recommended for children <2 years, adults >55 year, and anyone during outbreaks of meningococcal disease.
Neither meningococcal vaccine should be associated with adverse outcomes if used during pregnancy given that both are inactivated products. In one study of pregnant women vaccinated with MPSV4 in the third trimester, mothers had an appropriate antibody response with titers reaching a protective level. However, only selective antibodies crossed the placenta and neonatal antibody titers dropped to control levels within 3 months of delivery. Based on a recent systematic review, there has been no association with MPSV4 use during pregnancy and teratogenesis, preterm labor, or spontaneous abortion. There are no randomized, placebo-controlled trials or large observational cohorts included in the systematic review.
Measles, Mumps, Rubella
Measles, caused be a paramyxovirus, can be marked clinically by rash, diarrhea, otitis media, and in more severe cases bronchopenumonia or encephalitis. During pregnancy it is associated with increased rates of preterm birth, spontaneous abortion, and low birth weight. mumps, another paramyxovirus, presents with flulike symptoms and the classic bilateral parotitis. Infection during the first trimester of pregnancy has been associated with miscarriage. Rubella caused by a togavirus, is characterized by a nonspecific constellation of lymphadenopathy, arthralgias, fever, and transient erythematous rash. Infection during pregnancy can be devastating with resultant spontaneous abortion, fetal demise, and major congenital anomalies. Congenital rubella syndrome describes the associated fetal anomalies including deafness, ophthalmologic abnormalities, cardiac defects, and neurological damage.
Two doses of the MMR combination vaccine is part of the routine childhood vaccination. Additionally,
undergraduate and graduate students should receive two doses of MMR or provide evidence of immunity to all three viruses prior to enrollment. MMR is a live attenuated vaccine and thus contraindicated in pregnancy. The risk of fetal harm or infection due to the vaccine is theoretical, however. Due to severe consequences of infection with measles, mumps, and especially rubella during pregnancy, it has been determined that the risk does not outweigh the benefit of vaccination.
Varicella
Chicken pox is the results of infection with the varicella-zoster virus (VZV), a member of the herpes virus family. The illness is characterized by pruritic rash that typically last 4 to 7 days, during which time the individual is highly contagious. The virus is transmitted by direct contact and inhalation of aerosolized particles from skin or respiratory tract lesions. Infection during pregnancy can lead to neonatal varicella, herpes zoster (shingles) early in life, and congenital varicella syndrome, which is marked by low birth weight, limb hypoplasia, scarring of the skin, and numerous other anomalies.
The varicella vaccine is a monovalent live attenuated vaccine recommended as a two-dose regimen for all children. Similar to the MMR vaccine, varicella is contraindicated in pregnancy due to the unknown risk to the fetus and theoretical risk of active infection from live virus within the vaccine. Analogous to inadvertent rubella vaccination in early pregnancy, no cases of congenital varicella have been reported following inadvertent varicella vaccination 3 months before or at any time during pregnancy based on the VARIVAX Pregnancy Registry cosponsored by Merck and Company, Inc. and the CDC.
PROCEDURE:
Pregnancy is a particularly vulnerable period for VPD-associated complications for both mother and baby. Tdap
1. All women should informed about the flu vaccine during pregnancy, with strong encouragement for those with a history of asthma.
2. The CDC recommends Tdap vaccine after 20 weeks’ gestation for women who have not previously received the vaccine.
3. If the Tdap vaccine is not administered during pregnancy, Tdap should be given immediately postpartum. 4. Tdap should be administered to pregnant women who are due for decennial tetanus-diptheria booster
5. Currently, only one lifetime dose of Tdap is recommended with continued decennial tetanus-diphtheria booster vaccines thereafter.
Hepatitis A
6. Mothers with blood clotting factor deficiency or receiving clotting factor concentrates should be offered the hepatitis A vaccine.
Hepatitis B
7. Inquire about hepatitis B vaccine in client history and/or assess hepatitis titer with client’s consent. Pneumococcal
8. Women with asthma, diabetes, cochlear implants, immunodeficiences, or those who smoke or use alcohol should be counseled on the benefits of obtaining a pneumococcal disease.
Meningococcal Disease
9. As there are no available safety data on MCV4 use in pregnancy, vaccination with MPSV4 is recommended for pregnant women only if significant risk factor is present.
Measles, Mumps, Rubella
10. MMR is a live attenuated vaccine and thus contraindicated in pregnancy.
11. Women of childbearing potential should be asked if they are pregnant prior to being vaccinated with the MMR vaccine and should be counseled not to become pregnant for 28 days following vaccination. Of note, baed on data from the CDC Vaccine in Pregnancy Registry, no congenital disease has been reported after inadvertent first-trimester vaccination.
12. All women should be screened for rubella immunity early in pregnancy.
13. Immediate postpartum vaccination is recommended by the CDC for all women found to be rubella-susceptible to prevent potential risk in subsequent pregnancies and reduce the risk of exposure for the neonate.
14. Although rubella virus can be excreted in breastmilk and transmitted to the neonate following
immunization in the postpartum setting, neonatal infection remains asymptomatic; therefore breastfeeding is not a contraindication for postpartum vaccination.
Varicella
15. Per CDC recommendations, all pregnant women should be screened for VZV immunity by history of infection, history of vaccination, or VZV immunoglobulin G serology.
16. VZV-susceptible women should be informed of the risk of infection during pregnancy and counseled to immediately contact their nurse-midwife in case of exposure.
17. If exposed, pregnant women should receive varicella-zoster immunoglobulin promptly. 18. If chickenpox develops, treatment with oral antivirals, such as acyclovir, should be initiated.
19. Mothers who are or suspected to be VZV-susceptible should receive two doses of vaccine postpartum - the first immediately postpartum and the second 4 to 8 weeks later.
Traveling Vaccinations
20. Pregnant women traveling outside of the United States to countries with endemic VPDs should be advised to visit the CDC travel Web site for country-specific recommendations and determination of risk factors that may increase risk of disease acquisition or associated complications during pregnancy.
REFERENCES:
Swamy, G. K., & Garcia-Putman, R. (2012). Vaccine-Preventable Diseases in Pregnancy. Am J Perinatology, 30, 89-98.