Postpartum varicella vaccination: is the vaccine virus excreted in breast milk?

Maternal vaccination as an additional approach to improve the protection of the nursling: Anti-infective properties of breast milk

Human milk constitutes a secretion with unique functions of both nourishing the nursling and providing protection against enteric and respiratory infections, mainly due to its content of secretory IgA antibodies but also due to the presence of a plethora of bioactive factors. Specific IgA antibodies are produced locally by plasma cells derived from B lymphocytes that migrate from other mucosae to the mammary gland during lactation, particularly from the gastrointestinal and respiratory tracts. Therefore, here, the authors will provide a comprehensive review of the content and functions of different nutritional and bioactive anti-infectious components from breast milk, such as oligosaccharides, lactoferrin, haptocorrin, α-lactalbumin, k-casein, lysozyme, lactoperoxidase, mucin, fatty acids, defensins, cytokines and chemokines, hormones and growth factors, complement proteins, leukocytes and nucleic acids, including microRNAs, among many others, and the induction of antibody responses in breast milk after maternal vaccination with several licensed vaccines, including the anti-SARS-CoV-2 vaccine preparations used worldwide. Currently, in the midst of the pandemic, maternal vaccination has re-emerged as a crucial source of passive immunity to the neonate through the placenta and breastfeeding, considering that maternal vaccination can induce specific antibodies if performed during pregnancy and after delivery. There have been some reports in the literature about milk IgA antibodies induced by bacterial antigens or inactivated virus vaccines, such as anti-diphtheria-tetanus-pertussis, anti-influenza viruses, anti-pneumococcal and meningococcal polysaccharide preparations. Regarding anti-SARS-CoV-2 vaccines, most studies demonstrate elevated levels of specific IgA and IgG antibodies in milk with virus-neutralizing ability after maternal vaccination, which represents an additional approach to improve the protection of the nursling during the entire breastfeeding period.

Congenital and Perinatal Varicella Infections

Varicella-zoster virus (VZV) is a human pathogen of the α-herpesvirus family. Some fetuses infected in utero around 8-20 weeks of pregnancy show signs of congenital varicella syndrome (CVS). Infants born to mothers who develop varicella within 5 days before and 2 days after delivery can experience severe disease with increased mortality. The best diagnostic modality is polymerase chain reaction (PCR), which can be done using vesicular swabs or scrapings, scabs from crusted lesions, tissue from biopsy samples, and cerebrospinal fluid. The prevention and management of varicella infections include vaccination, anti-VZV immunoglobulin, and specific antiviral drugs. In this article, we have reviewed the characteristics of VZV, clinical manifestations, management of perinatal infections, and short- and long-term prognosis.

Comprehensive Overview of Vaccination during Pregnancy in Europe

Vaccinations during pregnancy can protect the mother from several infections, thus blocking vertical transmission. Furthermore, through passive antibody transfer, the newborn can be protected against some infections in the first months of life until their own vaccination regimen is initiated and completed at the appropriate age. Pregnancy can be considered a high-risk condition that increases vulnerability to infectious diseases with potentially unfavorable evolution. We present the current knowledge on vaccination during pregnancy in Europe as a useful information source for different health workers involved in prenatal care. Many European countries implement vaccination policies specifically designed for pregnant women, but there is great heterogeneity among programs. Recommendations on vaccination during pregnancy must be based on current high-quality scientific data. The decisions must be made for each individual case, depending on the associated conditions or special circumstances, with a concomitant assessment of the potential benefits and risks to both the pregnant patient and the fetus. Many vaccines are well-tolerated in pregnant women, with no clinically meaningful injection site reactions, systemic symptoms, or vaccine-related serious adverse events.

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.

[Perinatal varicella: fetal and neonatal risks and management]

La survenue d'une varicelle clinique en cours de grossesse est rare, pouvant entrainer des risques maternels et fœtaux. La varicelle maternelle périnatale peut entrainer une varicelle néonatale potentiellement grave, notamment en cas d'éruptions maternelles survenant entre 5 jours avant et 2 jours après l'accouchement. Nous rapportons huit observations de nouveau-nés de mères ayant eu une varicelle en péri-partum dans le but de synthétiser, l'état actuel des connaissances sur le risque de ce virus et d'essayer d'élaborer un protocole de prise en charge. Il s'agit d'une étude descriptive menée au centre de maternité et de néonatologie de Sousse, sur une période de 10 ans. Huit nouveau-nés ont été inclus dans l'étude. Le diagnostic était fait avant l'accouchement chez 7 mères. Une seule femme avait développé sa varicelle 3 jours après l'accouchement. Cinq nouveau-nés étaient symptomatiques à l'admission. Ils avaient tous des lésions cutanées typiques de la varicelle, trois parmi eux avaient une atteinte respiratoire associée. La prise en charge était basée sur l'isolement des nouveau-nés, les soins locaux, et le traitement par Acyclovir. L'évolution était favorable dans tous les cas. La survenue d'une varicelle au cours de la grossesse reste possible dans les pays ou la vaccination n'est pas encore accessible à tous. Les risques de complications maternelles et fœtales qu'elle occasionne justifient une prise en charge spécifique et bien codifiée.

Microbiology laboratory and the management of mother-child varicella-zoster virus infection

Varicella-zoster virus, which is responsible for varicella (chickenpox) and herpes zoster (shingles), is ubiquitous and causes an acute infection among children, especially those aged less than six years. As 90% of adults have had varicella in childhood, it is unusual to encounter an infected pregnant woman but, if the disease does appear, it can lead to complications for both the mother and fetus or newborn. The major maternal complications include pneumonia, which can lead to death if not treated. If the virus passes to the fetus, congenital varicella syndrome, neonatal varicella (particularly serious if maternal rash appears in the days immediately before or after childbirth) or herpes zoster in the early years of life may occur depending on the time of infection. A Microbiology laboratory can help in the diagnosis and management of mother-child infection at four main times: (1) when a pregnant woman has been exposed to varicella or herpes zoster, a prompt search for specific antibodies can determine whether she is susceptible to, or protected against infection; (2) when a pregnant woman develops clinical symptoms consistent with varicella, the diagnosis is usually clinical, but a laboratory can be crucial if the symptoms are doubtful or otherwise unclear (atypical patterns in immunocompromised subjects, patients with post-vaccination varicella, or subjects who have received immunoglobulins), or if there is a need for a differential diagnosis between varicella and other types of dermatoses with vesicle formation; (3) when a prenatal diagnosis of uterine infection is required in order to detect cases of congenital varicella syndrome after the onset of varicella in the mother; and (4) when the baby is born and it is necessary to confirm a diagnosis of varicella (and its complications), make a differential diagnosis between varicella and other diseases with similar symptoms, or confirm a causal relationship between maternal varicella and malformations in a newborn.

Viral infections in pregnancy: advice for healthcare workers

BACKGROUND

Healthcare workers (HCWs) have the potential for increased exposure to infectious disease resulting from the provision of patient care. Pregnancy can confer specific problems in some infections for the mother and her unborn child.

AIMS

To discuss the viral infections encountered in the UK that constitute a particular risk to the pregnant HCW: human immunodeficiency virus, hepatitis B virus, hepatitis C virus, varicella-zoster virus, herpes simplex virus, human parvovirus B19, cytomegalovirus, rubella, measles, enteroviruses, mumps and influenza. Evidence for nosocomial transmission, clinical aspects specific to pregnancy, and recommendations to protect the pregnant HCW at work are included.

METHODS

Medline, EMBASE and Pubmed were searched using a list of keywords specific to each viral infection, including 'nosocomial', 'occupational' and 'healthcare workers'. References from the bibliographies of articles identified were reviewed for relevant material.

FINDINGS

The evidence for increased risk in the healthcare setting for many of these infections, outside of outbreaks, is weak, possibly because of the application of standard protective infection control measures or because risk of community exposure is greater. The pregnant HCW should be advised on protective behaviour in both settings. Potential interventions include vaccination and reducing the likelihood of exposure through universal precautions, infection control and redeployment.

CONCLUSION

Protection of the pregnant HCW is the responsibility of the individual, antenatal care provider and employer, and is made possible through awareness of the risks and potential interventions both before and after exposure. If exposure occurs or if the HCW develops an infective illness, urgent specialist advice is required.

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.

Varicella in the fetus and newborn

Varicella (chickenpox) in pregnancy is unusual because most women of childbearing age are immune. It can, however, cause significant morbidity for the pregnant woman and in rare cases cause congenital varicella syndrome. The incidence of congenital varicella syndrome after maternal varicella during the first two trimesters is <1% across multiple cohort studies. Maternal infection in the third trimester is not associated with congenital varicella syndrome, but the infant may develop herpes zoster during the first one or two years. Maternal infection just before or after delivery presents a high risk for disseminated varicella in the infant. Serious infection can be prevented with passive antibody prophylaxis and antiviral therapy. Maternal herpes zoster does not result in adverse fetal or neonatal outcomes.

Varicella and the pregnant woman: prevention and management

Infection with varicella zoster virus (VZV) is often considered a childhood 'right of passage'; however, primary infection occurring in women of child-bearing age can have significant adverse consequences both for the mother and for her fetus. During the first trimester, primary VZV infection may result in stillbirth or a baby born with the stigmata of the congenital varicella syndrome, while infection in the peripartum period can result in neonatal varicella, which carries a significant mortality rate despite appropriate antiviral therapy. Varicella in pregnant women can progress to pneumonitis and other severe sequelae that may also compromise the viability of the fetus. Exposure to VZV most commonly occurs in the community or from children in the household, but occasionally, exposure may occur in the hospital environment. Determining a woman's serostatus prior to pregnancy is advised, as effective vaccines are now available and should be administered to non-pregnant seronegative women of child-bearing age. Clinical practice guidelines for management of a pregnant woman exposed to VZV are presented.

Varicella vaccine exposure during pregnancy: data from 10 Years of the pregnancy registry

BACKGROUND

The Pregnancy Registry for Varivax (Merck) was established to monitor for congenital varicella syndrome or other birth defects in the offspring of women who were exposed to varicella vaccine while pregnant.

METHODS

The registry receives voluntary reports from health care providers or consumers about women given the vaccine 3 months before or during pregnancy. Follow-up is conducted to obtain and classify pregnancy outcomes. All reports are evaluated for the presence of birth defects. Outcomes from prospectively reported pregnancy exposures are used to calculate rates and 95% confidence intervals.

RESULTS

From 17 March 1995 through 16 March 2005, 981 women were enrolled. Pregnancy outcomes were available for 629 prospectively enrolled women. Among the 131 live births to varicella-zoster virus-seronegative women, there was no evidence of congenital varicella syndrome (rate, 0% [95% confidence interval [CI], 0%-6.7%]), and major birth defects were observed in 3 infants (rate, 3.7% [95% CI, 0.8%-10.7%]).

CONCLUSIONS

Although the numbers of exposures are not sufficient to rule out a very low risk, data collected in the pregnancy registry to date do not support a relationship between the occurrence of congenital varicella syndrome or other birth defects and varicella vaccine exposure during pregnancy.

VZV infection in pregnancy: a retrospective review over 5 years in Sheffield and discussion on the potential utilisation of varicella vaccine in prevention

OBJECTIVES

To study retrospectively the epidemiology, demography and clinical issues related to varicella in pregnancy in a UK city over a 5-year period and help inform the debate on the potential of varicella immunisation in prevention.

METHODS

The hospital records of pregnant women with varicella receiving care at the Regional Department of Infection and Tropical Medicine in Sheffield between 1997 and 2002 were reviewed. Data on pregnant women with varicella not presenting acutely to medical care were obtained. The use of Varicella Zoster Immune Globulin (VZIG) in prevention of varicella during the same 5-year period was determined. The records from the maternity department of Sheffield Hospitals for women undergoing VZV antibody testing between January and December 2004 were reviewed. Data on annual number of deliveries were recorded and the neonatology database used as a source of information regarding effects of chickenpox on the baby.

RESULTS

The incidence of varicella infection in pregnancy was at least 6 per 10,000 deliveries. Nineteen pregnant women with varicella were admitted to hospital. Three had pneumonia. Infection occurred in the first pregnancy in a quarter of cases. The minimum cost for all cases admitted to hospital during this period (basic costs per day) was 20,520 pounds sterling. The cost of VZIG use for chickenpox during the same period adjusted for the population size was 10,881 pounds sterling. This was not a comprehensive health economic study and did not attempt to assess additional GP, midwifery, obstetric or social costs nor costs associated with those who did not attend hospital. Two hundred and thirty-three women underwent VZV antibody test during 2004 usually after contact with chickenpox. Sixty percent of women in contact with chickenpox did not present to their GP or hospital immediately.

CONCLUSION

Varicella in pregnancy may be associated with significant morbidity and health care cost and prevention by immunisation is desirable. Though targeted vaccination is attractive, screening in pregnancy followed by a post-partum varicella immunisation programme would fail to protect 25% and would be associated with logistical challenges not occurring with rubella immunisation. Varicella is now a preventable disease by immunisation. Exposure in pregnancy with or without infection has financial costs related to antibody testing and prophylaxis. Infection in pregnancy may be associated with additional costs and potential morbidity to mother and baby. Potential immunisation strategies are considered.