Serum concentrations, efficacy, and safety of a new, intravenously administered varicella zoster immune globulin in pregnant women

Varicella Zoster in pregnancy

Chickenpox during pregnancy can cause serious complications for both mother and fetus. This includes varicella pneumonia in the mother, fetal varicella syndrome and varicella of newborn. Primary prevention includes vaccination against varicella infection and is part of standard childhood immunisation programme in many countries. Timely post-exposure prophylaxis of susceptible pregnant women with varicella zoster immunoglobulin is key to preventing chickenpox during pregnancy and its adverse fetomaternal sequelae. Antiviral therapy and appropriate supportive treatment improve maternal and neonatal outcomes.

No. 274-Management of Varicella Infection (Chickenpox) in Pregnancy

OBJECTIVE

To review the existing data regarding varicella zoster virus infection (chickenpox) in pregnancy, interventions to reduce maternal complications and fetal infection, and antepartum and peripartum management .

METHODS

The maternal and fetal outcomes in varicella zoster infection were reviewed, as well as the benefit of the different treatment modalities in altering maternal and fetal sequelae.

EVIDENCE

Medline was searched for articles and clinical guidelines published in English between January 1970 and November 2010.

VALUES

The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care. Recommendations for practice were ranked according to the method described in that report (Table).

RECOMMENDATIONS

Varicella zoster immune globulin (VARIZIG) administration up to 10 days after varicella exposure in pregnant women, immunocompromised participants, and infants: Varicella outcomes and safety results from a large, open-label, expanded-access program

Introduction

Despite vaccination, there were more than 100,000 annual cases of varicella in the United States in 2013–2014. Individuals at highest risk of developing severe or complicated varicella include immunocompromised people, preterm infants, and pregnant women. Varicella zoster immune globulin (human) (VARIZIG) is recommended by the CDC for postexposure prophylaxis to prevent or attenuate varicella-zoster virus infection in high-risk individuals. Contemporary information on administration of VARIZIG is limited.

Methods

This open-label, expanded-access program provided VARIZIG to physician-identified, high-risk participants exposed to varicella. Participants included immunocompromised children/adults, infants (preterm, newborns whose mothers had varicella onset within 5 days before or 2 days after delivery, and those aged <1 year), and pregnant women. VARIZIG (125 IU/10 kg [up to 625 IU]) was administered intramuscularly, ideally within 96 hours, but up to 10 days, postexposure. Incidence of varicella rash and severity (>100 pox, pneumonia, or encephalitis) were assessed up to 42 days after administration.

Results

The varicella outcome population (n = 507) included 263 immunocompromised participants (32 adults, 231 children), 137 pregnant women, 105 infants, and 2 healthy adults with no history of varicella. Varicella incidence was 4.5% in immunocompromised participants, 7.3% in pregnant women, and 11.5% in infants. The incidence of varicella was similar when comparing VARIZIG administration ≤ 96 hours vs > 96 hours (up to 10 days) postexposure in the entire population (6.2% vs. 9.4%, respectively), and also in each subgroup. Of 34 participants with varicella, 5 developed > 100 pox and 1 developed pneumonia and encephalitis. There were no product-related deaths and only 1 serious adverse event (serum sickness) considered probably related to VARIZIG.

Conclusion

Postexposure administration of VARIZIG was associated with low rates of varicella in high-risk participants, regardless of when administered within 10 days postexposure. VARIZIG was well-tolerated and safe in high-risk participants.

Humoral Immune Responses Against Zika Virus Infection and the Importance of Preexisting Flavivirus Immunity

The recent emergence of Zika virus (ZIKV) in the western hemisphere has been linked to Guillain-Barre syndrome, congenital microcephaly, and devastating ophthalmologic and neurologic developmental abnormalities. The vast geographic spread and adverse disease outcomes of the 2015-2016 epidemic have elevated ZIKV from a previously understudied virus to one of substantial public health interest worldwide. Recent efforts to dissect immunological responses to ZIKV have provided significant insights into the functional quality and antigenic targets of ZIKV-induced B-cell responses. Several groups have demonstrated immunological cross-reactivity between ZIKV and other flaviviruses and have identified antibodies capable of both cross-neutralization, as well as antibody-dependent enhancement (ADE) of ZIKV infection. However, the impact of preexisting flavivirus immunity on ZIKV pathogenesis, the generation of protective responses, and in utero transmission of ZIKV infection remain unclear. Given the widespread endemicity of DENV in the areas most effected by the current ZIKV outbreak, the possibility of ADE is especially concerning and may pose unique challenges to the development and deployment of safe and immunogenic ZIKV vaccines. Here, we review current literature pertaining to ZIKV-induced B-cell responses and humoral cross-reactivity and discuss relevant considerations for the development of vaccines and therapeutics against ZIKV.

Management of chickenpox in pregnant women: an Italian perspective

Chickenpox is a highly contagious disease caused by primary infection of varicella zoster virus (VZV). The disease is spread worldwide and is usually benign but, in some groups of population like pregnant women, can have a severe outcome. Due to a not optimal vaccination coverage, a relatively high number of childbearing-aged women in a European country such as Italy tested seronegative for VZV and so are currently at risk of acquiring chickenpox during pregnancy, especially if they live in contact with children for family or work reasons. Only few data are available about the risk of infection in this setting: the incidence of chickenpox may range from 1.5 to 4.6 cases/1000 childbearing females and from 1.21 to 6 cases/10,000 pregnant women, respectively. This review is aimed to focus on the epidemiology and the clinical management of exposure to chickenpox during pregnancy. Particular emphasis is given to the accurate screening of childbearing women at the time of the first gynecological approach - the females who tested susceptible to infection can be counseled about the risks and instructed on procedure should contact occur - and to the early prophylaxis of the at-risk exposure. Lastly, the achievement of adequate vaccination coverage of the Italian population remains a cornerstone in the prevention of chickenpox in pregnancy.

Small Molecules and Antibodies for Zika Therapy

Zika virus (ZIKV) infection during pregnancy can cause devastating congenital abnormities or fetal demise. Zika virus infection could also cause Guillain-Barré syndrome in adults. Mosquito control, vaccine, and therapeutics are 3 potential, effective means to prevent ZIKV infection. Here we review the current status of ZIKV drug discovery. Both small molecule inhibitors and therapeutic antibodies have been identified, some of which have shown promising efficacy in mouse models. Most inhibitors were identified through screening US Food and Drug Administration-approved drugs and clinical trial compounds; however, none of them were potent enough to justify a ZIKV clinical trial. Such a repurposing approach has also been pursued for dengue therapy, with several compounds tested in clinical trials showing no clinical benefits. Because pregnant women are the main target population for ZIKV treatment, therapeutic candidates could be developed through a 2-stage path. The first stage should demonstrate safety and efficacy in nonpregnant patients. Once efficacy has been demonstrated in nonpregnant patients, the candidates should be rapidly advanced to stage 2 for safety and efficacy evaluation in pregnant patients. The 2-stage developmental path is supported by previous results from trials with other viral infections that showed that treatment of pregnant women with antiviral drugs or hyperimmunoglobulins significantly reduced congenital abnormalities in neonates.

High-level cellular and humoral immune responses in Guinea pigs immunized intradermally with a heat-inactivated varicella-zoster virus vaccine

The threat of varicella and herpes zoster in immunocompromised individuals necessitates the development of a safe and effective varicella-zoster virus (VZV) vaccine. The immune responses of guinea pigs to the intradermal (i.d.) or subcutaneous (s.c.) administration of a heat-inactivated or live VZV vaccine were investigated. Relative to nonimmunized animals, a single 399-PFU dose of vaccine induced nonsignificant increases in gamma interferon (IFN-γ), granzyme B, and perforin mRNA expression in the splenocytes of all groups, while two i.d. administrations of the inactivated vaccine increased IFN-γ mRNA expression significantly (P < 0.005). A single 1,995-PFU dose significantly increased the expression of IFN-γ mRNA in the groups receiving the vaccine either i.d. (P < 0.005) or s.c. (P < 0.05), that of granzyme B mRNA in the groups immunized i.d. with the inactivated (P < 0.005) or live (P < 0.005) vaccine, and that of perforin mRNA in the animals that received the inactivated vaccine i.d. (P < 0.005). Importantly, increases in the expression of IFN-γ (P = 0.025), granzyme B (P = 0.004), and perforin (P > 0.05) mRNAs were observed in the animals immunized i.d. with 1,995 PFU of inactivated vaccine relative to those immunized s.c. with the same dose. The proportion of animals expressing IFN-γ mRNA mirrored the proportion expressing IFN-γ protein (correlation coefficient of 0.88). VZV glycoprotein-specific and virus-neutralizing antibodies were produced with no significant intergroup differences. A booster i.d. administration of the 399-PFU dose of heat-inactivated vaccine enhanced the antibody responses. These results demonstrate that i.d. administration of an inactivated VZV vaccine can be an efficient mode of immunization against VZV.

The role of VariZIG in pregnancy

Varicella infection during pregnancy is associated with serious maternal and fetal complications such as congenital varicella syndrome, maternal pneumonia and neonatal varicella. Pregnant women are ineligible to receive the varicella vaccination, thus women who lack evidence of immunity to varicella are at an increased risk for developing a varicella infection if exposed to a contagious individual. Presently, post-exposure prophylaxis involves the administration of a varicella zoster immunoglobulin (VariZIG™) to prevent or reduce the severity of an infection. The US FDA recently approved VariZIG for licensure and recommend that it be administered as soon as possible following VZV exposure, ideally within 96 h for greatest effectiveness. The following review critically examines the role of VariZIG in post-exposure prophylaxis of varicella during pregnancy.

Management of varicella infection (chickenpox) in pregnancy

OBJECTIVE

To review the existing data regarding varicella zoster virus infection (chickenpox) in pregnancy, interventions to reduce maternal complications and fetal infection, and antepartum and peripartum management.

METHODS

The maternal and fetal outcomes in varicella zoster infection were reviewed, as well as the benefit of the different treatment modalities in altering maternal and fetal sequelae.

EVIDENCE

Medline was searched for articles and clinical guidelines published in English between January 1970 and November 2010.

VALUES

The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care. Recommendations for practice were ranked according to the method described in that report (Table).

RECOMMENDATIONS

1. Varicella immunization is recommended for all non-immune women as part of pre-pregnancy and postpartum care. (II-3B) 2. Varicella vaccination should not be administered in pregnancy. However, termination of pregnancy should not be advised because of inadvertent vaccination during pregnancy. (II-3D) 3. The antenatal varicella immunity status of all pregnant women should be documented by history of previous infection, varicella vaccination, or varicella zoster immunoglobulin G serology. (III-C) 4. All non-immune pregnant women should be informed of the risk of varicella infection to themselves and their fetuses. They should be instructed to seek medical help following any contact with a person who may have been contagious. (II-3B) 5. In the case of a possible exposure to varicella in a pregnant woman with unknown immune status, serum testing should be performed. If the serum results are negative or unavailable within 96 hours from exposure, varicella zoster immunoglobulin should be administered. (III-C) 6. Women who develop varicella infection in pregnancy need to be made aware of the potential adverse maternal and fetal sequelae, the risk of transmission to the fetus, and the options available for prenatal diagnosis. (II-3C) 7. Detailed ultrasound and appropriate follow-up is recommended for all women who develop varicella in pregnancy to screen for fetal consequences of infection. (III-B) 8. Women with significant (e.g., pneumonitis) varicella infection in pregnancy should be treated with oral antiviral agents (e.g., acyclovir 800 mg 5 times daily). In cases of progression to varicella pneumonitis, maternal admission to hospital should be seriously considered. Intravenous acyclovir can be considered for severe complications in pregnancy (oral forms have poor bioavailability). The dose is usually 10 to 15 mg/kg of BW or 500 mg/m² IV every 8 h for 5 to 10 days for varicella pneumonitis, and it should be started within 24 to 72 h of the onset of rash. (III-C) 9. Neonatal health care providers should be informed of peripartum varicella exposure in order to optimize early neonatal care with varicella zoster immunoglobulin and immunization. (III-C) Varicella zoster immunoglobulin should be administered to neonates whenever the onset of maternal disease is between 5 days before and 2 days after delivery. (III-C).

Varicella-zoster virus (chickenpox) infection in pregnancy

Congenital varicella syndrome, maternal varicella-zoster virus pneumonia and neonatal varicella infection are associated with serious fetomaternal morbidity and, not infrequently, mortality. Vaccination against varicella-zoster virus can prevent the disease, and outbreak control limits the exposure of pregnant women to the infectious agent. Maternal varicella-zoster immunoglobulin administration before rash development, with or without antiviral medication, can modify the progression of the disease.

Pre-travel vaccination and medical prophylaxis in the pregnant traveler

BACKGROUND

Practitioners are often fearful of giving vaccinations and prophylactic medications to pregnant travelers. And yet pregnancy is often a time of heightened danger from travel-related infections and illnesses.

METHOD

Literature search and communication with researchers.

RESULTS

With a few exceptions, there is little systematic research regarding the use of prophylactic medications and vaccines during pregnancy. Case reports and small studies do, however, indicate an increased risk in pregnancy from many of the preventable illnesses, and there is some data to support the use of preventive measures.

CONCLUSIONS

The authors present some non-medical interventions that may be used to limit exposure to a number of disease processes. They then review the available information regarding the safety and efficacy of routine and travel-related vaccines as well as prophylactic medications for malaria, diarrhea, motion sickness and altitude sickness. When there are no obstetrical or medical contraindications, travel-related illness can usually be safely prevented during pregnancy in much the same ways as in the non-pregnant state.

Infektionen mit Herpes-simplex- und Varicella-zoster-Viren in der Schwangerschaft

Primary infections with herpes simplex virus (HSV) and varicella-zoster virus (VZV) may lead to severe illness in pregnancy. Both diseases may be associated with transplacental virus transmission and fetal infection. Such infections can lead to intrauterine death, severe malformations and premature birth; the fetal/congenital varicella syndrome is well-defined. Herpes genitalis and varicella at the time of labor may lead to life threatening neonatal-herpes or varicella of the newborn. Currently neither active immunization nor neutralizing immunoglobulin is available for HSV infections. VZV-seronegative women in child-bearing age can be vaccinated and pregnant women exposed to VZV can be given specific immunoglobulins. While an infection is rarely blocked, the severity is generally reduced. For severe disease antiviral treatment is necessary, with valacyclovir and acyclovir represents the drugs of choice. Primary or recurrent overt disease of the genital tract at the time of delivery an indication for caesarean section. Suppression of recurrent genital herpes during the last weeks of pregnancy with valacyclovir and acyclovir reduces the need for surgical intervention. Neonates exposed to VZV should receive specific immunoglobulin. If neonates show signs of either infection, immediate treatment with acyclovir must be initiated.