我が国に、varicella-zoster immune globulinないため悩みました。
- 水痘ワクチン (定期接種は通常通り)
- γグロブリン 水痘力価が高い製品ロット使用
Varicella-zoster viral (VZV) infection in the newborn is due to either vertical transmission from the mother during pregnancy or delivery, or acquired after birth from the environment or infected care providers.
●Congenital varicella syndrome occurs in infants whose mothers are infected between 8 and 20 weeks gestation. Clinical manifestations vary and include Cicatricial skin lesions, ocular defects (eg, cataracts, chorioretinitis, Horner syndrome, microphthalmos, and nystagmus), and abnormalities of the limb (eg, hypoplasia of bone and muscle) and central nervous system (eg, cortical atrophy, seizures, and cognitive impairment).
●Neonatal varicella is a serious illness with a mortality rate as high as 30 percent.
●Neonates born to mothers with VZV infection, or who were exposed within two weeks of delivery are at high risk for neonatal varicella. The risk and severity of illness increases when maternal infection occurs less than five days prior to delivery because there is insufficient time for the development and transfer of maternal antibody.
●The clinical manifestations of neonatal varicella vary from a mild illness similar to chickenpox in older children to a disseminated disease involving the liver, lung, and central nervous system.
●The diagnosis of varicella usually is made clinically based upon the characteristic appearance of skin lesions. VZV infection is confirmed by detection of the virus in vesicular fluid culture, or by direct fluorescent antigen and polymerase chain reaction (PCR) in vesicular scrapings, swabs, and, for PCR, cerebral spinal fluid.
●Postexposure prophylaxis with varicella-zoster immune globulin (VariZIG) is recommended for infants born to symptomatic mothers around the time of delivery, preterm infants with gestational age (GA) ≥28 weeks born to mothers without immunity, and preterm infants <28 weeks.
●Mothers with active disease or those who are seronegative with a history of exposure 6 to 21 days before admission must be isolated from other patients including their infants. The newborn is isolated from the mother until she is no longer infectious. Any infant who develops varicella is isolated.
●We recommend a 10-day course of acyclovir (30 mg/kg per day in 3 divided doses IV) to treat neonatal varicella.
●Breastfeeding is encouraged in infants exposed to or infected with varicella.
Exposed infants in the NICU usually are cohorted. They are isolated from new patients admitted between 8 and 21 days after exposure. VariZIG should be given to all NICU patients with seronegative mothers and to all preterm infants <28 weeks gestation or ≤1000 g birth weight regardless of maternal immune status. Infants who received VariZIG should be isolated from new patients for 28 days.
VariZIG — Varicella-zoster immune globulin (VariZIG) is a purified human immune globulin preparation made from plasma containing high levels of anti-varicella antibodies.
Postexposure prophylaxis has been shown to either prevent varicella in exposed neonates, ameliorate the course, or delay the disease in patients in whom the infection was not fully prevented.
The Advisory Committee on Immunization Practices (ACIP) and the Centers for Disease Control and Prevention (CDC) recommend administration of VariZIG to newborns who have had a significant exposure to VZV
●Neonates whose mothers have signs and symptoms of varicella around the time of delivery (within five days before or two days after).
●Hospitalized premature infants born at ≥28 weeks of gestation or more whose mothers do not have signs of immunity.
●Hospitalized premature infants born at <28 weeks of gestation or who weigh <1000 grams at birth regardless of maternal history of varicella or vaccination.
In addition, some experts suggest VariZIG for exposed infants within the first two weeks of life whose mothers do not have evidence of immunity to VZV.
The recommended dose is 125 units (1 vial) intramuscularly. VariZIG is lyophilized and must be reconstituted for intramuscular administration.
In 2012, the US Food and Drug Administration (FDA) approved VariZIG following exposure to VZV to reduce the severity of VZV infection for the groups described above as well as for immunocompetent adults who lack evidence of immunity to VZV. VariZIG is lyophilized and must be reconstituted for intramuscular administration.
When postexposure prophylaxis is indicated, passive immunization with VariZIG should be offered as soon as possible. The FDA has extended the window of passive immunization after varicella exposure from 4 to 10 days.
If VariZIG cannot be administered within 96 hours of exposure, then intravenous immunoglobulin (IVIG) should be considered. If IVIG is unavailable, some experts would recommend prophylaxis with acyclovir.