Human Metapneumovirus and Other Respiratory Viral Infections during Pregnancy and Birth, Nepal

Burden of human metapneumovirus infections among children with acute respiratory tract infections attending a Tertiary Care Hospital, Kathmandu

BACKGROUND

Acute respiratory infections (ARIs) are one of the most common causes of mortality and morbidity worldwide. Every year millions of children suffer from viral respiratory tract infections (RTIs) ranging from mild to severe illnesses. Human Metapneumovirus (HMPV) is among the most frequent viruses responsible for RTIs. However, HMPV infections and their severity among children have not been explored yet in Nepal.

PURPOSE

Therefore, the study was focused on HMPV infections and other potential viral etiologies or co-infections using multiplex PCR among children attending Kanti Children's Hospital and assessed the clinical characteristics of the infections as well as found the co-infections. A hospital-based cross-sectional study was designed and a convenience sampling method was used to enroll children of less than 15 years with flu-like symptoms from both outpatients and inpatients departments over three months of the study period.

RESULTS

HMPV infection (13.3%) was the most predominant infection among the different viral infections in children with ARIs in Kanti Children's Hospital. The HMPV was more prevalent in the age group less than three years (21.8%). Cough and fever were the most common clinical features present in all children infected with HMPV followed by rhinorrhea, sore throat, and wheezing. HMPV-positive children were diagnosed with pneumonia (42.9%), bronchiolitis (28.5%), upper respiratory tract infections (14.3%), and asthma (14.3%). The prevalence of HMPV was high in late winter (14.3%) followed by early spring (13.5%).

CONCLUSIONS

This study provides the baseline information on HMPV and associated co-infection with other respiratory viruses for the differential diagnosis based on molecular methods and also the comparison of clinical presentations among the different respiratory syndromes.

Human Maternal-Fetal Interface Cellular Models to Assess Antiviral Drug Toxicity during Pregnancy

Pregnancy is a period of elevated risk for viral disease severity, resulting in serious health consequences for both the mother and the fetus; yet antiviral drugs lack comprehensive safety and efficacy data for use among pregnant women. In fact, pregnant women are systematically excluded from therapeutic clinical trials to prevent potential fetal harm. Current FDA-recommended reproductive toxicity assessments are studied using small animals which often do not accurately predict the human toxicological profiles of drug candidates. Here, we review the potential of human maternal-fetal interface cellular models in reproductive toxicity assessment of antiviral drugs. We specifically focus on the 2- and 3-dimensional maternal placental models of different gestational stages and those of fetal embryogenesis and organ development. Screening of drug candidates in physiologically relevant human maternal-fetal cellular models will be beneficial to prioritize selection of safe antiviral therapeutics for clinical trials in pregnant women.

From maternal breath to infant's cells: Impact of maternal respiratory infections on infants 'immune responses

In utero exposure to maternally-derived antigens following chronic infection is associated with modulation of infants 'immune response, differential susceptibility to post-natal infections and immune response toward vaccines. The maternal environment, both internal (microbiota) and external (exposure to environmental microbes) also modulates infant's immune response but also the clinical phenotype after birth. Vertical transmission of ubiquitous respiratory pathogens such as influenza and COVID-19 is uncommon. Evidence suggest that in utero exposure to maternal influenza and SARS-CoV-2 infections may have a significant impact on the developing immune system with activation of both innate and adaptive responses, possibly related to placental inflammation. Here in, we review how maternal respiratory infections, associated with airway, systemic and placental inflammation but also changes in maternal microbiota might impact infant's immune responses after birth. The clinical impact of immune modifications observed following maternal respiratory infections remains unexplored. Given the high frequencies of respiratory infections during pregnancy (COVID-19, influenza but also RSV and HMPV), the impact on global child health could be important.

Respiratory viral infections during pregnancy: effects of SARS-CoV-2 and other related viruses over the offspring

Little is known about the consequences of viral infection for pregnant woman or for the fetus. This issue became important with the appearance of the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). The infection with SARS-CoV-2 causes a respiratory syndrome known as COVID-19. The fast spreading around the world and the fact that without a treatment or vaccine humans are completely exposed, converts emerging viral diseases in a significant risk for pregnant women and their infants. At this time, during SARS-CoV-2 pandemics pregnant women are not considered as a risk population and little is known about the effects of viral infections over the offspring although the amount of emerging evidence showing detrimental effects for the mother and the fetus. This issue highlights the importance to understand the effects of viral infections during pregnancy. In this work, we analyze the effects of viral infections, like SARS-CoV-2 and other related viruses during pregnancy over the mother and the consequences for the offspring.

Respiratory viral coinfection in a birth cohort of infants in rural Nepal

BACKGROUND

Acute respiratory illnesses are a leading cause of global morbidity and mortality in children. Coinfection with multiple respiratory viruses is common. Although the effects of each virus have been studied individually, the impacts of coinfection on disease severity are less understood.

METHODS

A secondary analysis was performed of a maternal influenza vaccine trial conducted between 2011 and 2014 in Nepal. Prospective weekly household-based active surveillance of infants was conducted from birth to 180 days of age. Mid-nasal swabs were collected and tested for respiratory syncytial virus (RSV), rhinovirus, influenza, human metapneumovirus (HMPV), coronavirus, parainfluenza (HPIV), and bocavirus by RT-PCR. Coinfection was defined as the presence of two or more respiratory viruses detected as part of the same illness episode.

RESULTS

Of 1730 infants with a respiratory illness, 327 (19%) had at least two respiratory viruses detected in their primary illness episode. Of 113 infants with influenza, 23 (20%) had coinfection. Of 214 infants with RSV, 87 (41%) had coinfection. The cohort of infants with coinfection had increased occurrence of fever lasting ≥ 4 days (OR 1.4, 95% CI: 1.1, 2.0), and so did the subset of coinfected infants with influenza (OR 5.8, 95% CI: 1.8, 18.7). Coinfection was not associated with seeking further care (OR 1.1, 95% CI: 0.8, 1.5) or pneumonia (OR 1.2, 95% CI: 0.96, 1.6).

CONCLUSION

A high proportion of infants had multiple viruses detected. Coinfection was associated with greater odds of fever lasting for four or more days, but not with increased illness severity by other measures.

INFECTIONS IN PREGNANCY WITH COVID-19 AND OTHER RESPIRATORY RNA VIRUS DISEASES ARE RARELY, IF EVER, TRANSMITTED TO THE FETUS: EXPERIENCES WITH CORONAVIRUSES, HPIV, hMPV RSV, AND INFLUENZA

SARS-CoV-2, the agent of COVID-19, is similar to two other coronaviruses, SARS-CoV and MERS-CoV, in causing life-threatening maternal respiratory infections and systemic complications. Because of global concern for potential intrauterine transmission of SARS-CoV-2 from pregnant women to their infants, this report analyzes the effects on pregnancy of infections caused by SARS-CoV-2 and other respiratory RNA viruses, and examines the frequency of maternal-fetal transmission with SARS-CoV-2, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), influenza, respiratory syncytial virus (RSV), parainfluenza (HPIV) and metapneumovirus (hMPV). There have been no confirmed cases of intrauterine transmission reported with COVID-19 or any other coronavirus infections. Influenza virus, despite causing approximately one billion annual infections globally, has only a few cases of confirmed or suspected intrauterine fetal infections reported. RSV is in an unusual cause of illness among pregnant women, and with the exception of one premature infant with congenital pneumonia, no other cases of maternal-fetal infection are described. Parainfluenza virus and human metapneumovirus can produce symptomatic maternal infections but do not cause intrauterine fetal infection. In summary, it appears that the absence thus far of maternal-fetal transmission of the SARS-CoV-2 virus during the COVID-19 pandemic is similar to other coronaviruses, and is also consistent with the extreme rarity of suggested or confirmed cases of intrauterine transmission of other respiratory RNA viruses. This observation has important consequences for pregnant women as it appears that if intrauterine transmission of SARSCoV-2 does eventually occur, it will be a rare event. Potential mechanisms of fetal protection from maternal viral infections are also discussed.

An international cohort study of birth outcomes associated with hospitalized acute respiratory infection during pregnancy

OBJECTIVES

Findings during the 2009 pandemic suggest severe maternal infection with pandemic influenza had adverse perinatal health consequences. Limited data exist evaluating the perinatal health effects of severe seasonal influenza and non-influenza infections during pregnancy.

METHODS

A retrospective cohort of pregnant women from Australia, Canada, Israel, and the United States was established using birth records to identify pregnancies and birth outcomes and hospital and laboratory testing records to identify influenza and non-influenza associated acute respiratory or febrile illness (ARFI) hospitalizations. ARFI hospitalized women were matched to non-hospitalized women (1:4) by country and season of conception. Log-binomial regression was used to estimate the relative risk (aRR) of preterm birth (PTB), small-for-gestational-age (SGA), and low birthweight (LBW) birth, adjusting for pre-existing medical conditions, maternal age, and parity.

RESULTS

950 pregnant women hospitalized with an ARFI were matched with 3,800 non-hospitalized pregnant women. Compared to non-hospitalized women, risk of PTB was greater among women hospitalized with influenza-associated ARFI (aRR: 1.57; 95% CI: 1.15-2.15) and non-influenza ARFI (aRR: 2.78; 95% CI: 2.12-3.65). Similar results were observed for LBW; there were no associations with SGA birth.

CONCLUSIONS

ARFI hospitalization during pregnancy was associated with increased risk of PTB and LBW.

Immunobiological aspects of vaccines in pregnancy: Maternal perspective

Immunization during pregnancy is an efficient strategy to protect both the mother and the newborn infant against infectious pathogens. Pregnant women have an increased susceptibility to severe infections caused by some pathogens, but the mechanisms involved remain poorly understood. Pregnancy is associated with dynamic changes in maternal immune system that are critical for tolerance of the fetus. These changes could also play an important role in shaping maternal immune components that are transferred to the newborn infant following natural infection or vaccination to prevent infectious diseases in early life. As the momentum for maternal immunization is growing, there is a need to increase our understanding of the immunobiology of maternal immunization in order to better prevent infectious diseases in the pregnant women and the young infant.

A Cross-sectional Surveillance Study of the Frequency and Etiology of Acute Respiratory Illness Among Pregnant Women

Background

Other than influenza, little is known about the consequences of viral acute respiratory illness (ARI) on pregnant women and fetuses. Our objectives were to determine the frequency of ARI due to respiratory viruses and the associated clinical outcomes during pregnancy.

Methods

Pregnant women in their second or third trimester were enrolled if they reported having symptoms of ARI or were healthy within the preceding 2 weeks. Nasopharyngeal secretions were evaluated for respiratory viruses by molecular diagnostic assays. Clinical outcomes were evaluated at enrollment and via a follow-up telephone-based questionnaire 2 weeks later.

Results

There were 155 pregnant participants, with 81 ARI cases and 91 healthy controls. Acute lower respiratory tract illness (ALRTI) was identified in 29 cases (36%). Human rhinovirus (HRV), respiratory syncytial virus (RSV), and influenza virus accounted for 75% of virus-positive cases of ALRTI. Cases with ALRTI often reported a longer duration of illness, history of allergies, symptoms of wheezing, shortness of breath, or chest pain, and use of prescription medication. Two cases with ALRTI reported decreased fetal movement; a third case with ALRTI was hospitalized.

Conclusions

In over one third of ARI cases, participants had symptoms consistent with ALRTI. Infection with HRV, RSV, or influenza virus was commonly detected in patients with ALRTI. Viral ALRTI during pregnancy appears to be common and is associated with significant morbidity.

RSV, Antibodies and the Developing World

Respiratory syncytial virus remains a major cause of infantile respiratory illness globally. Infants in the developing world experience the highest burden of mortality and morbidity. Risk factors associated with respiratory syncytial virus infection and progression to severe disease include household crowding, preterm birth and low birth weight. Maternally-derived antibody has a role in protection of infants through transplacental antibody transfer and breast milk antibody. Promising prevention strategies that are under development include vaccination during pregnancy and monoclonal antibody administration at birth.

Molecular characterization of influenza viruses from women and infants in Sarlahi, Nepal

We used RT-PCR-electrospray ionization-mass spectrometry to identify subtypes and strains of influenza viruses detected during a maternal influenza immunization study in Nepal from May 2011 to April 2014. Hemagglutinin (HA) gene amino acid (aa) sequences of inferred reference strains were compared to those of the vaccines to determine impact of aa relatedness on vaccine efficacy (VE) and disease severity. Three influenza subtypes and many strains were identified. A(H3N2) strains with less than 13 aa differences in HA compared to vaccine strains (matched) showed higher VE than strains with 13 or more differences (mismatched). Yamagata lineage B strains, which were mismatched to the Victoria strain in the vaccine, demonstrated lower VE compared to Victoria strains. Differences in VE were not statistically significant. All A(H1N1pdm) matched the vaccine strain, with 10 or fewer aa differences. Except for women infected with vaccine-matched strains of influenza A, clinical signs and symptoms did not differ between vaccinated and unvaccinated participants.