Evaluation of preterm births and birth defects in liveborn infants of US military women who received smallpox vaccine

Mpox Virus in Pregnancy, the Placenta, and Newborn

CONTEXT.—

Before its eradication, the smallpox virus was a significant cause of poor obstetric outcomes, including maternal and fetal morbidity and mortality. The mpox (monkeypox) virus is now the most pathogenic member of the Orthopoxvirus genus infecting humans. The 2022 global mpox outbreak has focused attention on its potential effects during pregnancy.

OBJECTIVE.—

To understand the comparative effects of different poxvirus infections on pregnancy, including mpox virus, variola virus, vaccinia virus, and cowpox virus. The impact on the pregnant individual, fetus, and placenta will be examined, with particular attention to the occurrence of intrauterine vertical transmission and congenital infection.

DATA SOURCES.—

The data are obtained from the authors' cases and from various published sources, including early historical information and contemporary publications.

CONCLUSIONS.—

Smallpox caused maternal and perinatal death, with numerous cases reported of intrauterine transmission. In endemic African countries, mpox has also affected pregnant individuals, with up to a 75% perinatal case fatality rate. Since the start of the 2022 mpox outbreak, increasing numbers of pregnant women have been infected with the virus. A detailed description is given of the congenital mpox syndrome in a stillborn fetus, resulting from maternal-fetal transmission and placental infection, and the potential mechanisms of intrauterine infection are discussed. Other poxviruses, notably vaccinia virus and, in 1 case, cowpox virus, can also cause perinatal infection. Based on the historical evidence of poxvirus infections, mpox remains a threat to the pregnant population, and it can be expected that additional cases will occur in the future.

Monkeypox and the perinatal period: what does maternal-fetal medicine need to know?

BACKGROUND

After the global elimination of smallpox, monkeypox has become the most threatening orthopoxvirus to human health. Very few studies have been reported on pregnant women and newborns. In the case of monkeypox infection, the virus can cause serious adverse pregnancy events in women, which can lead to fetal or neonatal death.

DATA SOURCES

We made a comprehensive review after an extensive literature search in the PubMed/Medline database and websites concerning smallpox and monkeypox.

RESULTS

Two case reports reported a total of nine pregnant women, six of whom had fetal deaths. In the autopsy of a stillbirth, researchers found that the placenta was infected with monkeypox virus, but the mechanism of infection remains unclear. Smallpox vaccine should be administered to acutely exposed pregnant women and newborns. Several novel recombinant vaccinia immunogloblin (rVIG) and human-specific monoclonal antibodies are being developed for the prevention and treatment of monkeypox virus infection. After the fetus was delivered, the newborn should take a bath as soon as possible to remove the amniotic fluid and dirt from the body. The appropriate isolation protocol for the newborn should be selected according to the infection status of the mother. It is not known whether monkeypox virus is present in breast milk, and pasteurized breast milk can be given to newborns when breastfeeding is considered.

CONCLUSION

This review presents an overview of monkeypox in the perinatal period and guides the future research direction.

Obstetric Outcomes in Military Servicewomen: Emerging Knowledge, Considerations, and Gaps

The number of women in the U.S. military is dramatically increasing. Similarly, the roles of active-duty women are greatly expanding, thus exposing them to new occupational risks. Determining the impact of pregnancy outcomes for women while in the military is difficult due to changing exposures over time, difficulty in utilizing appropriate comparison groups, and the lack of prospective investigations. Despite these limitations, it was concerning that the available data suggest that servicewomen delivering within 6 months of their first deployment have an increased preterm birth risk (adjusted odds ratio [aOR]: 2.1), and those with three prior deployments have an even greater risk (aOR: 3.8). Servicewomen also have an increased risk of hypertensive disorders with a rate of 13% compared with 5% in the general obstetric population. Furthermore, depression is higher for women who deploy after childbirth and are exposed to combat when compared with those who have not deployed since the birth of their child (aOR: 2.01). Due to the importance of this issue, prospective research designs are necessary to better understand and address the unique health care needs of this population.

Safety of Administering Live Vaccines During Pregnancy: A Systematic Review and Meta-Analysis of Pregnancy Outcomes

Live-attenuated vaccines (LAV) are currently contraindicated during pregnancy, given uncertain safety records for the mother-infant pair. LAV might, however, play an important role to protect them against serious emerging diseases, such as Ebola and Lassa fever. For this systematic review we searched relevant databases to identify studies published up to November 2019. Controlled observational studies reporting pregnancy outcomes after maternal immunization with LAV were included. The ROBINS-I tool was used to assess risk of bias. Pooled odds ratios (OR) were obtained under a random-effects model. Of 2831 studies identified, fifteen fulfilled inclusion criteria. Smallpox, rubella, poliovirus, yellow fever and dengue vaccines were assessed in these studies. No association was found between vaccination and miscarriage (OR 0.98, 95% CI 0.87-1.10), stillbirth (OR 1.04, 95% CI 0.74-1.48), malformations (OR 1.09, 95% CI 0.98-1.21), prematurity (OR 0.99, 95% CI 0.90-1.08) or neonatal death (OR 1.06, 95% CI 0.68-1.65) overall. However, increased odds of malformations (OR 1.24; 95% CI 1.03-1.49) and miscarriage after first trimester immunization (OR 4.82; 95% CI 2.38-9.77) was found for smallpox vaccine. Thus, we did not find evidence of harm related to LAV other than smallpox with regards to pregnancy outcomes, but quality of evidence was very low. Overall risks appear to be small and have to be balanced against potential benefits for the mother-infant pair.

Selection of Higher Risk Pregnancies into Veterans Health Administration Programs: Discoveries from Linked Department of Veterans Affairs and California Birth Data

OBJECTIVE

To describe variation in payer and outcomes in Veterans' births.

DATA/SETTING

Secondary data analyses of deliveries in California, 2000-2012.

STUDY DESIGN

We performed a retrospective, population-based study of all live births to Veterans (confirmed via U.S. Department of Veterans Affairs (VA) enrollment records), to identify payer and variations in outcomes among: (1) Veterans using VA coverage and (2) Veteran vs. all other births. We calculated odds ratios (aOR) adjusted for age, race, ethnicity, education, and obstetric demographics.

METHODS

We anonymously linked VA administrative data for all female VA enrollees with California birth records.

PRINCIPAL FINDINGS

From 2000 to 2012, we identified 17,495 births to Veterans. VA covered 8.6 percent (1,508), Medicaid 17.3 percent, and Private insurance 47.6 percent. Veterans who relied on VA health coverage had more preeclampsia (aOR 1.4, CI 1.0-1.8) and more cesarean births (aOR 1.2, CI 1.0-1.3), and, despite similar prematurity, trended toward more neonatal intensive care (NICU) admissions (aOR 1.2, CI 1.0-1.4) compared to Veterans using other (non-Medicaid) coverage. Overall, Veterans' birth outcomes (all-payer) mirrored California's birth outcomes, with the exception of excess NICU care (aOR 1.15, CI 1.1-1.2).

CONCLUSIONS

VA covers a higher risk fraction of Veterans' births, justifying maternal care coordination and attention to the maternal-fetal impacts of Veterans' comorbidities.

Deployment and Preterm Birth Among US Army Soldiers

With increasing integration of women into combat roles in the US military, it is critical to determine whether deployment, which entails unique stressors and exposures, is associated with adverse reproductive outcomes. Few studies have examined whether deployment increases the risk of preterm birth; no studies (to our knowledge) have examined a recent cohort of servicewomen. We therefore used linked medical and administrative data from the Stanford Military Data Repository for all US Army soldiers with deliveries between 2011 and 2014 to estimate the associations of prior deployment, recency of deployment, and posttraumatic stress disorder with spontaneous preterm birth (SPB), adjusting for sociodemographic, military-service, and health-related factors. Of 12,877 deliveries, 6.1% were SPBs. The prevalence was doubled (11.7%) among soldiers who delivered within 6 months of their return from deployment. Multivariable discrete-time logistic regression models indicated that delivering within 6 months of return from deployment was strongly associated with SPB (adjusted odds ratio = 2.1, 95% confidence interval: 1.5, 2.9). Neither multiple past deployments nor posttraumatic stress disorder was significantly associated with SPB. Within this cohort, timing of pregnancy in relation to deployment was identified as a novel risk factor for SPB. Increased focus on servicewomen's pregnancy timing and predeployment access to reproductive counseling and effective contraception is warranted.

Neonatal death: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data

More than 40% of all deaths in children under 5 years of age occur during the neonatal period: the first month of life. Immunization of pregnant women has proven beneficial to both mother and infant by decreasing morbidity and mortality. With an increasing number of immunization trials being conducted in pregnant women, as well as roll-out of recommended vaccines to pregnant women, there is a need to clarify details of a neonatal death. This manuscript defines levels of certainty of a neonatal death, related to the viability of the neonate, who confirmed the death, and the timing of the death during the neonatal period and in relation to immunization of the mother.

Dismantling the Taboo against Vaccines in Pregnancy

Vaccinating pregnant women in order to protect them, the fetus, and the child has become universal in no way at all. Prejudice in health professionals add to fears of women and their families. Both these feelings are not supported by even the smallest scientific data. Harmlessness for the mother and the child has been observed for seasonal, pandemic, or quadrivalent influenza, mono, combined polysaccharide or conjugated meningococcal or pneumococcal, tetanus toxoid, acellular pertussis, human papillomavirus, cholera, hepatitis A, Japanese encephalitis, rabies, anthrax, smallpox, yellow fever, mumps, measles and rubella combined, typhoid fever, inactivated or attenuated polio vaccines, and Bacillus Calmétte Guerin vaccines. Instead, the beneficial effects of influenza vaccine for the mother and the child as well as of pertussis vaccine for the child have been demonstrated. Obstetrician-gynecologists, general practitioners, and midwives must incorporate vaccination into their standard clinical care. Strong communication strategies effective at reducing parental vaccine hesitancy and approval of regulatory agencies for use of vaccines during pregnancy are needed. It must be clear that the lack of pre-licensure studies in pregnant women and, consequently, the lack of a statement about the use of the vaccine in pregnant women does not preclude its use in pregnancy.

Defending against smallpox: a focus on vaccines

Smallpox has shaped human history, from the earliest human civilizations well into the 20th century. With high mortality rates, rapid transmission, and serious long-term effects on survivors, smallpox was a much-feared disease. The eradication of smallpox represents an unprecedented medical victory for the lasting benefit of human health and prosperity. Concerns remain, however, about the development and use of the smallpox virus as a biological weapon, which necessitates the need for continued vaccine development. Smallpox vaccine development is thus a much-reviewed topic of high interest. This review focuses on the current state of smallpox vaccines and their context in biodefense efforts.

Risks Associated With Smallpox Vaccination in Pregnancy: A Systematic Review and Meta-analysis

OBJECTIVE

To estimate the maternal and fetal risks of smallpox vaccination during pregnancy.

DATA SOURCES

MEDLINE, Web of Science, EMBASE, Global Health, ClinicalTrials.gov, and CINHAL from inception to September 2014.

METHODS OF STUDY SELECTION

We included published articles containing primary data regarding smallpox vaccination during pregnancy that reported maternal or fetal outcomes (spontaneous abortion, congenital defect, stillbirth, preterm birth, or fetal vaccinia).

TABULATIONS, INTEGRATION, AND RESULTS

The primary search yielded 887 articles. After hand-searching, 37 articles were included: 18 articles with fetal outcome data and 19 case reports of fetal vaccinia. Outcomes of smallpox vaccination in 12,201 pregnant women were included. Smallpox vaccination was not associated with an increased risk of spontaneous abortion (pooled relative risk [RR] 1.03, confidence interval [CI] 0.76-1.41), stillbirth (pooled RR 1.03, CI 0.75-1.40), or preterm birth (pooled RR 0.84, CI 0.62-1.15). When vaccination in any trimester was considered, smallpox vaccination was not associated with an increased risk of congenital defects (pooled RR 1.25, CI 0.99-1.56); however, first-trimester exposure was associated with an increased risk of congenital defects (2.4% compared with 1.5%, pooled RR 1.34, CI 1.02-1.77). No cases of fetal vaccinia were reported in the studies examining fetal outcomes; 21 cases of fetal vaccinia were identified in the literature, of which three neonates survived.

CONCLUSION

The overall risk associated with maternal smallpox vaccination appears low. No association between smallpox vaccination and spontaneous abortion, preterm birth, or stillbirth was identified. First-trimester vaccination was associated with a small increase in congenital defects, but the effect size was small and based on limited data. Fetal vaccinia appears to be a rare consequence of maternal smallpox vaccination but is associated with a high rate of fetal loss.

Maternal immunization: an update for pediatricians

The immunization of women during pregnancy can protect both the mother and her infant against serious infectious diseases. The prevention of infection through maternal immunization reduces the risk of exposure to the baby, results in higher concentrations of transplacentally transferred pathogen-specific maternal antibodies to the newborn, and provides protection to the infant during a period of vulnerability. The benefits of vaccinating pregnant women outweigh any theoretic risk when there is a risk of exposure to an infectious disease that threatens the mother or the newborn's health. Toxoids and inactivated virus or bacterial vaccines are safe and cause no harm to the mother or fetus. Live vaccines, viral or bacterial, are contraindicated during pregnancy as a precaution because of the theoretic risk of infection of the fetus. However, there has been no evidence to date of direct fetal injury after the administration of live viral vaccines to pregnant women. The administration of immune globulin preparations to pregnant women results in no known risks to the fetus. In the United States, vaccines recommended in pregnancy include the seasonal influenza vaccine, tetanus toxoid, and the pertussis vaccine as a combined tetanus-diphtheria toxoid and acellular pertussis vaccine (Tdap). Pregnant women who travel or who have unavoidable exposures to vaccine-preventable diseases should be immunized. Breast-feeding is not a contraindication to the vaccination of mothers with inactivated and most live vaccines. Women who are not immune to rubella should be immunized after delivery. Similarly, the influenza and Tdap vaccinations may be administered postpartum in women who were not vaccinated during pregnancy.

Vaccines in the pipeline: the path from development to use in the United States

New vaccines in the United States go through a complex process on their path from development to the domestic market involving an intricate partnership of public and private agencies and organizations. This process includes licensure by the US Food and Drug Administration, the development of recommendations by the Advisory Committee on Immunization Practices, and safety oversight post-licensure. This article examines the roles of the US Food and Drug Administration and the Centers for Disease Control and Prevention as well as certain professional organizations in governing the testing, marketing, and usage of new vaccines. Vaccines currently in development to treat numerous infectious and noninfectious diseases are also examined and compared with frameworks of domestic vaccine development prioritization, past and present, as assessed by the Institute of Medicine.

Developmental toxicity testing of vaccines

Preventative and therapeutic vaccines are increasingly used during pregnancy and present special considerations for developmental toxicity testing. The various components of the vaccine formulation (i.e., protein or polysaccharide antigen, adjuvants, and excipients) need to be assessed for direct effects on the developing conceptus. In addition, possible adverse influences of the induced antibodies on fetal and/or postnatal development need to be evaluated. A guidance document on the preclinical testing of preventative and therapeutic vaccines for developmental toxicity was issued by the FDA in 2006. Preclinical studies are designed to assess possible influences of vaccines on pre- and postnatal development. The choice of model animal for these experiments is influenced by species differences in the timing and extent of the transfer of the induced maternal antibodies to the fetus. The cross-placental transport of maternal immunoglobulins generally only occurs in late gestation and tends to be greater in humans and monkeys than in non-primate species. For many vaccines, the rabbit shows a greater rate of prenatal transfer of the induced antibodies than rodents. For biotechnology-derived vaccines that are not immunogenic in lower species, nonhuman primates may be the only appropriate models. It may be advisable to test new adjuvants using the ICH study designs for conventional pharmaceuticals in addition to the developmental toxicity study with the final vaccine formulation.

Birth defects in infants born in 1998-2004 to men and women serving in the U.S. military during the 1990-1991 Gulf War era

BACKGROUND

Concerns about reproductive health persist among U.S. military members who served in the 1990-1991 Gulf War. This study explores the long-term impact of 1990-1991 Gulf War deployment on the prevalence of birth defects among infants of Gulf War veterans.

METHODS

Health care data from the Department of Defense Birth and Infant Health Registry and demographic and deployment information from the Defense Manpower Data Center were used to identify infants born between 1998 and 2004 to both male and female 1990-1991 Gulf War veterans. Multivariable logistic regression models estimated the adjusted odds of any birth defect and eight specific birth defects among infants of deployers versus non-deployers. In addition, birth defects were evaluated among infants born to 1990-1991 Gulf War veterans with deployment-specific exposures.

RESULTS

Among 178,766 infants identified for these analyses, 3.4% were diagnosed with a birth defect in the first year of life. Compared to infants of non-deployers, infants of deployers were not at increased odds of being diagnosed with a birth defect, or any of eight specific birth defects, in the first year of life. A slightly increased prevalence of birth defects was observed among infants born to men who deployed to the 1990-1991 Gulf War for 153 to 200 days compared to those who deployed for 1 to 92 days. No other deployment-specific exposures were associated with birth defects in these infants.

CONCLUSIONS

The 1990-1991 Gulf War deployers, including those with specific exposures of concern, were not found to be at increased risk for having infants with birth defects 7 to 14 years after deployment.

Health outcomes among infants born to women deployed to United States military operations during pregnancy

BACKGROUND

Military professionals who deploy to combat operations may encounter hazards that could adversely affect reproductive health. Pregnant women are generally exempt from deployment to military operations; however, exposures to such environments may inadvertently occur. We investigated whether maternal deployment during pregnancy was associated with adverse health outcomes in infants.

METHODS

The United States Department of Defense Birth and Infant Health Registry identified infants born to military service women between 2002 and 2005, and defined their health outcomes at birth and in the first year of life. Multivariable modeling was applied to investigate preterm birth and birth defects among infants, based on maternal deployment experience during pregnancy.

RESULTS

Among 63,056 infants born to military women from 2002 to 2005, 22,596 were born to women with deployment experience in support of the current military operations before, during, or after their pregnancy. These included 2941 infants born to women who appeared to have been deployed some time during their first trimester of pregnancy. Compared to infants born to women who deployed at other times, or never deployed, exposed infants were not more likely to be born preterm, diagnosed with a major birth defect, or diagnosed with a malignancy.

CONCLUSIONS

In this exploratory analysis, infants born to women who inadvertently deployed to military operations during their pregnancy were not at increased risk of adverse birth or infant health outcomes. Future analyses should examine outcomes related to specific maternal exposures during deployment, and outcomes among the growing number of infants conceived after deployment.