Pregnant women are universally recognized as a high-risk group for complications arising from influenza and COVID-19 infections. Both the World Health Organization (WHO) and Norwegian health authorities strongly advise immunization during pregnancy, particularly in the second and third trimesters, to protect not only maternal health but also the neonatal immune system through transplacental antibody transfer. The WHO posits a vaccination coverage target of 75% for at-risk groups, including pregnant women, to achieve adequate herd immunity and prevent outbreaks. However, the Norwegian data indicates a stark discrepancy between guidelines and real-world uptake.

Utilizing linked data from the Medical Birth Registry Norway (MBRN) and the Norwegian Immunisation Registry (SYSVAK), the study meticulously tracked maternal immunization from October 2023 through September 2024. The analysis captured vaccination timing relative to pregnancy trimesters and delivery months, as well as demographic variables such as age and regional distribution. The findings unearthed a vaccination uptake of just 29.9% for influenza and a mere 12.1% for COVID-19 during pregnancy. Critically, only 11.4% of the cohort received both vaccines, elucidating significant missed opportunities for comprehensive maternal protection.

Temporal patterns in vaccine administration exhibited notable variations. Influenza vaccine uptake marginally improved from 16.4% in early October to approximately 26.4% by November, plateauing thereafter. Vaccination rates peaked among women delivering in February, with coverage reaching 50.8%, before declining in subsequent months. This temporal gradient suggests a potential correlation between seasonal influenza activity and vaccination timing, yet overall rates remain suboptimal. The COVID-19 vaccination followed a similar trajectory but at distinctly lower coverage levels, emphasizing compounded vulnerabilities.

One of the more perplexing aspects highlighted by the study is the dissonance between Norway’s high public trust in healthcare authorities and the low maternal vaccine uptake. Despite extensive communication strategies and evidence-based recommendations, practical and psychological barriers continue to hinder pregnant women’s vaccination decisions. Younger women, particularly those aged 25 and under, displayed the lowest uptake, suggesting age-related factors such as perceived risk, vaccine hesitancy, or access issues may be influential.

Geographical disparities further complicate the maternal immunization landscape within Norway. The highest vaccine coverage was observed in urbanized counties such as Oslo and Vestland, which likely benefit from better healthcare infrastructure and provider availability. Conversely, Northern Norway demonstrated the lowest vaccination rates, raising concerns about rural health inequities, logistic challenges, and potential sociocultural differences impacting immunization behaviors.

The study’s authors advocate for multifaceted interventions to bridge these immunization gaps. Removing financial barriers, especially given that the influenza vaccine incurs a cost while the COVID-19 vaccine is free, is critical. Enhancing accessibility through dedicated prenatal vaccination programs integrated into routine obstetric care visits could reduce reliance on self-initiated healthcare appointments. Furthermore, leveraging trusted sources of vaccine information tailored to the concerns of pregnant women may mitigate psychological hesitancy.

Importantly, international evidence cited by the researchers underscores the success of embedding free vaccinations like the pertussis vaccine into Norway’s maternal immunization schedule, which substantially improved uptake. Applying similar frameworks to influenza and COVID-19 vaccines could reinforce the normalization and prioritization of maternal immunization. The study’s implications extend beyond Norway, mirroring global challenges including inconsistent surveillance systems and fragmented integration of maternal vaccines into healthcare pathways.

The researchers call for comprehensive surveillance mechanisms to continually monitor maternal vaccination trends, allowing timely identification of gaps and evaluation of interventions. Such systems should ideally provide granular, real-time data to inform public health policy and address inequalities at multiple levels. Coordinated efforts across Europe and worldwide are imperative to elevate maternal immunization coverage and ultimately safeguard maternal and neonatal health on a broader scale.

Clinicians and public health professionals must recognize the critical window of opportunity that pregnancy represents for vaccination, harnessing trust in healthcare while effectively addressing logistical and psychosocial barriers. This study highlights an urgent need for innovative approaches that move beyond mere recommendations, striving for systematic integration, community engagement, and policy support to improve maternal vaccine uptake in Norway and globally.

In summary, Stecher et al.’s in-depth registry study is a clarion call to health systems worldwide: while scientific consensus affirms the safety and efficacy of influenza and COVID-19 vaccinations during pregnancy, actual coverage remains alarmingly insufficient. Without proactive, targeted interventions to dismantle financial, access-related, and informational barriers, pregnant women and their infants will continue to face preventable risks from these serious viral infections.

Subject of Research: People

Article Title: Missed opportunities for maternal immunisation against influenza and COVID-19, Norway, October 2023 to May 2024: a population-based registry study

News Publication Date: 19-Feb-2026

Web References: 10.2807/1560-7917.ES.2026.31.7.2500504

Keywords: Health and medicine, Vaccination, COVID 19 vaccines, Flu vaccines, Vaccine target, Pregnancy, Public health, Infectious diseases, Influenza, COVID 19

At the forefront of this evolving paradigm is the triad of immunological strategies: preventing viral entry, invoking maternal and placental immune defenses, and transferring immunological protection to the neonate. Blocking viral entry involves targeting viral surface proteins and receptors to preclude initial infection and is exemplified by recent advances employing small molecules and monoclonal antibodies that inhibit interactions such as the SARS-CoV-2 spike protein binding to ACE2. Concurrently, leveraging maternal and placental immunity entails understanding and manipulating the immune environment at the maternal-fetal interface to reduce viral transmission risk, while the administration of maternal vaccines or passive immunotherapies facilitates the transfer of protective antibodies, thereby fortifying neonatal immune defenses during the vulnerable postnatal period.

In the context of HIV, the cornerstone of prevention resides in comprehensive approaches that encompass pre-exposure prophylaxis (PrEP) for pregnant women, predominantly utilizing nucleoside reverse transcriptase inhibitors (NRTIs) known for their efficacy and placental permeability. Combinatorial antiretroviral therapy (ART), initiated early in pregnancy, substantially reduces vertical transmission. Yet, the neonatal period mandates vigilant postnatal prophylaxis, frequently tailored by maternal viral load metrics. Infants exposed to low maternal viremia generally receive short-course zidovudine monotherapy, whereas those with elevated exposure risk require intensified triple-drug regimens to preempt infection establishment. Diagnostic vigilance persists with periodic virologic testing extending well into infancy to detect early viral replication events, particularly during breastfeeding phases that pose ongoing transmission threats amid immature neonatal immunity.

Emerging therapeutic frontiers against HIV focus on neutralizing broad-spectrum monoclonal antibodies (bnAbs) engineered for enhanced viral targeting and improved pharmacokinetics through Fc domain modifications. These innovations include optimized placental transfer capabilities, extending the protective window for infants. Clinical trials are exploring bnAbs like leronlimab, which antagonize the CCR5 receptor critical for HIV entry, offering promising adjuncts to standard ART. Parallel advancements incorporate mRNA vaccine platforms designed to bolster bnAb precursor maturation, and gene editing modalities such as CRISPR-Cas9 aimed at excising latent viral reservoirs by targeting viral co-receptors and genome integration sites. The integration of immune checkpoint inhibitors seeks to augment immune surveillance against residual infected populations, although these sophisticated interventions necessitate cautious balancing of efficacy, toxicity, and socio-economic factors, especially in low-resource settings.

The phenomenon of vertical transmission of SARS-CoV-2 is infrequent but not negligible, prompting a nuanced approach to maternal and neonatal care. Maternal immunization with mRNA vaccines after 20 weeks of gestation emerges as a pivotal intervention, demonstrably reducing hospitalization rates in infants younger than six months by enhancing antibody transplacental transfer. The efficacy of this antibody transfer is highly dependent on factors such as timing within the gestational timeline—with the early third trimester identified as an optimal window—and biological variables including antibody subclass profiles, fetal sex, and the prevailing viral variants. These determinants collectively shape the degree of neonatal immune preparedness against SARS-CoV-2.

Upon birth, neonates born to SARS-CoV-2–positive or exposed mothers undergo serial RT-PCR testing at specified intervals to monitor infection status, mindful of the limited sensitivity in asymptomatic cases arising from low viral loads. Current care remains predominantly supportive, focusing on respiratory support proportional to disease severity with mechanical ventilation reserved for critical cases. Select infants benefit from antiviral therapy with remdesivir, informed by clinical severity. Protocols also advocate for antenatal corticosteroid administration, controlled delayed cord clamping, and measured mother-infant contact to mitigate infection risk while preserving bonding and breastfeeding opportunities. Importantly, sustained longitudinal follow-up is vital to identify and manage potential neurodevelopmental, cardiovascular, and immunological sequelae attributable to prenatal exposure, areas that remain under active investigation.

Interventional therapeutics targeting congenital SARS-CoV-2 exposure are advancing, with monoclonal antibodies such as bamlanivimab and casirivimab undergoing evaluation for prophylactic and therapeutic use in high-risk neonates, albeit tempered by concerns over immunosuppressive side effects. Investigative compounds addressing the ACE2 receptor—through molecules that inhibit receptor binding domains or deploy decoy receptors—alongside innovative mRNA immunotherapeutic strategies, herald a novel frontier in infection prevention. Additionally, maternal hyperinflammation during COVID-19 pregnancies invites immunomodulatory interventions including corticosteroids and IL-6 inhibitors to minimize fetal inflammatory injury, further underscoring the complexity of managing this viral threat.

Influenza virus poses a distinct clinical challenge, where direct vertical transmission remains exceedingly rare, yet maternal infection predisposes to heightened maternal and neonatal morbidity. Rapid diagnosis in neonates employs RT-PCR to confirm infection, enabling timely initiation of supportive care and antiviral therapy. Oseltamivir remains the antiviral of choice and is most effective when administered within 48 hours of symptom onset, though critical cases necessitate a more flexible therapeutic window. Maternal immunization against influenza is universally recommended throughout pregnancy, conferring dual protective benefits by reducing maternal morbidity and enhancing transplacental antibody transfer, which decreases infant influenza incidence markedly during early life. Nevertheless, waning maternal antibodies by eight weeks postnatally and the ineffectiveness of current vaccines in infants under six months highlight an urgent need for novel vaccine platforms tailored for early infancy.

Supplementing existing influenza treatments are emergent approaches including toll-like receptor 4 (TLR4) agonists demonstrating promising preclinical efficacy, repurposed host-targeted antivirals conferring broad-spectrum activity, and advanced neutralizing antibodies and engineered nanobodies designed to intercept hemagglutinin or neuraminidase function. Despite these innovations, clinical data regarding efficacy and safety in prenatally exposed infants remain sparse, underscoring a critical knowledge gap. Addressing this deficit demands integrative efforts combining maternal vaccination strategies, age-appropriate infant vaccines, and therapeutics optimized for neonatal physiology.

Across these viral challenges, a unifying theme is the dynamic interplay between maternal immunity, placental transfer mechanisms, and neonatal immune development, determining susceptibility and outcomes following prenatal viral exposure. The evolving landscape of immunoprophylaxis and antiviral therapeutics increasingly harnesses molecular insights into viral-host interactions, placental biology, and immune ontogeny, aiming to supplant empirical care with precision-medicine interventions. Advances in monoclonal antibody engineering, vaccine design leveraging mRNA technology, and gene editing illuminate a future where durable viral suppression and prevention may be achievable from conception through early infancy.

Comprehensive management also entails meticulous monitoring for adverse effects stemming from therapeutic interventions, particularly those involving novel agents with complex immunomodulatory profiles. In resource-limited environments, the scalability, affordability, and safety of such measures remain significant hurdles, necessitating tailored solutions that balance cutting-edge science with practical implementation.

Preventive immunization schedules for neonates and infants exposed to these viruses continue to adapt in response to emerging data, with particular caution exercised regarding live-attenuated vaccines in the context of HIV exposure due to risks of dissemination. Longitudinal surveillance of exposed infants provides critical insights into the natural history of infections and the effectiveness of therapeutic interventions, guiding iterative refinements in clinical guidelines.

The landscape of prenatal viral infections is also increasingly shaped by pathogen evolution, immune escape variants, and the complex biology of maternal-fetal immunology. This dynamic environment underscores the importance of flexible, evidence-based clinical frameworks that accommodate evolving scientific understanding while safeguarding the most vulnerable populations: the unborn and newborn infants.

Emergent research avenues include the optimization of antibody transfer through Fc receptor interactions, refinement of immunomodulatory treatments to attenuate maternal-fetal inflammation, and the development of nanoparticle-based vaccines promoting the induction of broadly neutralizing antibodies. Gene-editing technologies targeting integrated viral genomes and host co-receptors offer a tantalizing prospect for achieving viral eradication, though ethical and safety considerations remain paramount.

As precision immunotherapies progress, multidisciplinary collaboration across immunology, virology, obstetrics, and neonatology will be essential to translate benchside breakthroughs into bedside realities. With prenatal viral infections continuing to pose significant global health challenges, these integrated approaches represent a beacon of hope toward diminishing the burden of congenital and neonatal viral diseases, optimizing early immune protection, and ultimately preserving lifelong health trajectories for affected children.

Subject of Research: Prenatal viral infections and their mechanistic impact on maternal and fetal immunity, focusing on clinical management and preventive immunotherapeutic strategies.

Article Title: Mechanistic insights into the impact of prenatal viral infections on maternal and offspring immunity

Article References:
Salem, G.M., Azamor, T., Familiar-Macedo, D. et al. Mechanistic insights into the impact of prenatal viral infections on maternal and offspring immunity. npj Viruses 4, 7 (2026). https://doi.org/10.1038/s44298-026-00174-9

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s44298-026-00174-9