Immune and pathophysiologic profiling of antenatal coronavirus disease 2019 in the GIFT cohort: A Singaporean case-control study

COVID-19 can be severe in pregnant women, and have adverse consequences for the subsequent infant. We profiled the post-infectious immune responses in maternal and child blood as well as breast milk in terms of antibody and cytokine expression and performed histopathological studies on placentae obtained from mothers convalescent from antenatal COVID-19. Seventeen mother-child dyads (8 cases of antenatal COVID-19 and 9 healthy unrelated controls;34 individuals in total) were recruited to the Gestational Immunity For Transfer (GIFT) study. Maternal and infant blood, and breast milk samples were collected over the first year of life. All samples were analyzed for IgG and IgA against whole SARS-CoV-2 spike protein, the spike receptor-binding domain (RBD), and previously reported immunodominant epitopes, as well as cytokine levels. The placentae were examined microscopically. The study is registered at clinicaltrials.gov under the identifier NCT04802278. We found high levels of virus-specific IgG in convalescent mothers and similarly elevated titers in newborn children. Thus, antenatal SARS-CoV-2 infection led to high plasma titers of virus-specific antibodies in infants postnatally. However, this waned within 3–6 months of life. Virus neutralization by plasma was not uniformly achieved, and the presence of antibodies targeting known immunodominant epitopes did not assure neutralization. Virus-specific IgA levels were variable among convalescent individuals’ sera and breast milk. Antibody transfer ratios and the decay of transplacentally transferred virus-specific antibodies in neonatal circulation resembled that for other pathogens. Convalescent mothers showed signs of chronic inflammation marked by persistently elevated IL17RA levels in their blood. Four placentae presented signs of acute inflammation, particularly in the subchorionic region, marked by neutrophil infiltration even though > 50 days had elapsed between virus clearance and delivery. Administration of a single dose of BNT162b2 mRNA vaccine to mothers convalescent from antenatal COVID-19 increased virus-specific IgG and IgA titers in breast milk, highlighting the importance of receiving the vaccine even after natural infection with the added benefit of enhanced passive immunity.

Reactogenicity of mRNA- and Non-mRNA-Based COVID-19 Vaccines among Lactating Mother and Child Dyads.

The aims of the study are to: (a) Describe the reactogenicity of WHO-approved two mRNA (Pfizer-BioNTech, Moderna) and two non-RNA (Oxford-AstraZeneca, Sinovac) vaccines among lactating mother and child pairs, and (b) Compare and contrast the reactogenicity between mRNA and non-mRNA vaccines. A cross-sectional, self-reported survey was conducted amongst 1784 lactating women who received COVID-19 vaccinations. The most common maternal adverse reaction was a local reaction at the injection site, and the largest minority of respondents, 49.6% (780/1571), reported experiencing worse symptoms when receiving the second dose compared to the first dose. Respondents reported no major adverse effects or behavioural changes in the breastfed children for the duration of the study period. Among respondents who received non-mRNA COVID-19 vaccines, a majority reported no change in lactation, but those who did more commonly reported changes in the quantity of milk supply and pain in the breast. The more commonly reported lactation changes (fluctuations in breast milk supply quantity and pain in the breast) for the non-mRNA vaccines were similar to those of respondents who received mRNA vaccines. Our study, with a large, racially diverse cohort, further augments earlier reported findings in that the COVID-19 vaccines tested in this study did not cause any serious adverse events in our population for the duration of our survey period, although long-term effects are yet to be studied.

Reactogenicity of mRNA and non-mRNA Based COVID-19 Vaccines Among Lactating Mother and Baby Dyads (preprint)

The aims of the study are: a) Describe the reactogenicity of WHO-approved two mRNA (Pfizer-BioNTech, Moderna) and two non-RNA vaccines (Oxford-AstraZeneca, Sinovac) among lactating mother and baby pairs; and b) compare and contrast the reactogenicity between mRNA and non-mRNA vaccines. A cross-sectional, self-reported survey was conducted amongst 1784 lactating women who received COVID-19 vaccinations. The most common maternal adverse reaction was a local reaction at the injection site; the largest minority of respondents, 43.7% (780/1784), reported experiencing worse symptoms when receiving the second dose compared to the first dose. There were no major reported adverse effects or behavioural changes in the breastfed infants. Among the respondents who received non-mRNA COVID-19 vaccinations, a majority reported no change in lactation but those who did more commonly reported an increase in milk supply, decrease in milk supply and pain in the breast. The more commonly reported lactation changes (fluctuations in breastmilk supply and pain in the breast) for the non-mRNA vaccines were similar to that of respondents who received mRNA vaccines. Our study, with a large cohort and wide geographical and racial mix, further augments earlier reported findings that COVID-19 vaccines are safe for breastfeeding mothers and her children.

Effect of COVID-19 Pandemic on Influenza Vaccination Intention: A Meta-Analysis and Systematic Review.

Poorer outcomes have been reported with COVID-19 and influenza coinfections. As the COVID-19 pandemic rages on, protection against influenza by vaccination is becoming increasingly important. This study examines how COVID-19 has influenced influenza vaccination intentions from a global perspective. A literature search was conducted on Embase, PubMed, and CNKI from 1 January 2019 to 31 December 2021 for articles reporting rates of influenza vaccination pre-COVID-19 (19/20 season), and intention and/or uptake of influenza vaccination post-COVID-19 (20/21 season). The changes in vaccination intention and reasons for changes were reported. Subgroup analyses were performed by region, gender, age, and occupation. Newcastle Ottawa Scale was used for quality assessment of the articles. Twenty-seven studies with 39,193 participants were included. Among 22 studies reporting intention to vaccinate in 20/21, there was increased intention to vaccinate (RR 1.50, 95% CI 1.32-1.69, p < 0.001) regardless of age, gender, and occupation. The remaining five studies reporting vaccination intention and uptake in 20/21 showed a similar increase (RR 1.68, 95%CI 1.20-2.36). Important determinants include historical vaccine acceptance, and perception of influenza severity and vaccine safety. The COVID-19 pandemic has increased intention to vaccinate against influenza internationally. The pandemic could be a window of opportunity to promote influenza vaccination and decrease vaccine hesitancy.

Human Milk Antibodies after BNT162b2 Vaccination Exhibit Reduced Binding against SARS-CoV-2 Variants of Concern.

SARS-CoV-2-specific antibody responses are engendered in human milk after BNT162b2 vaccination. However, the emergence of variants of concern (VOCs) raises concerns about the specificity of and potential cross-protection mediated by milk antibody responses, which are crucial for passive immunity transferred from breastfeeding mothers to their infants. In this study, we collected milk samples at three different time points pre- and post-vaccination, and measured milk IgA antibody binding to the receptor binding domain (RBD) of the original Wuhan-Hu-1 strain, and the four VOCs, namely Alpha, Beta, Gamma and Delta. We report a significant level of anti-RBD IgA in milk collected at 4-6 weeks after the second dose of vaccination compared to pre-vaccination. We observed around a 30% reduction in binding to most VOCs, including the major circulating Delta variant, compared to the original Wuhan-Hu-1 strain. As COVID-19 vaccines may take some time to be approved for infants, these individuals remain at risk for severe disease and rely mainly on transferred passive immunity. Our findings support the current recommendations for vaccinating lactating women with the aim of transferring mucosal immunity to breastfeeding infants.

Breastfeeding Mother and Child Clinical Outcomes After COVID-19 Vaccination.

BACKGROUND: Pre-approval clinical trials of the Pfizer/BioNTech messenger RNA COVID-19 vaccine, BNT162b2 did not include participants who were breastfeeding. Therefore, there is limited evidence about outcomes of breastfeeding mother-child dyads and effects on breastfeeding after vaccination. RESEARCH AIMS: To determine: (1) solicited adverse effects (e.g., axillary lymphadenopathy, mastitis, and breast engorgement), which are unique to lactating individuals; and (2) systemic and local adverse effects of COVID-19 mRNA vaccine on mothers and potential effects on their breastfed infants. METHOD: This was a prospective cohort study of lactating healthcare workers (N = 88) in Singapore who received two doses of BNT162b2 vaccination (Pfizer/BioNTech). The outcomes of mother-child dyads within 28 days after the second vaccine dose were determined through a participant-completed questionnaire. RESULTS: Minimal effects related to breastfeeding were reported by this cohort; three of 88 (3.4%) participants had mastitis, one (1.1%) participant experienced breast engorgement, five of 88 (5.7%) participants reported cervical or axillary lymphadenopathy. There was no change in human milk supply after vaccination. The most common side effect was pain/redness/swelling at the injection site, which was experienced by 57 (64.8%) participants. There were no serious adverse events of anaphylaxis or hospital admissions. There were no short-term adverse effects reported in the infants of 67 lactating participants who breastfed within 72 hr after BNT162b2 vaccination. CONCLUSIONS: BNT162b2 vaccination was well tolerated in lactating participants and was not associated with short-term adverse effects in their breastfed infants. STUDY PROTOCOL REGISTRATION: The study protocol was registered at clinicaltrials.gov (NCT04802278).

Clinical features and outcomes of neonatal COVID-19: a systematic review

BackgroundIn general, children with COVID-19 have milder illness and better prognosis compared to adults. However, the neonatal population (from birth to 28 days of life) may be more vulnerable to severe COVID-19 disease due to the immaturity of neonatal immune system and possibility of in-utero infection from infected mothers. Comprehensive data on neonatal COVID-19 manifestations is currently lacking.ObjectivesWe aimed to determine the clinical manifestations and outcomes of neonates with COVID-19, and characterise these clinical characteristics based on illness severity.MethodsA systematic review (CRD42020183500) was conducted following the PRISMA guidelines with Embase, PubMed, and China Knowledge Resource Integrated (CNKI) databases until 1 August 2020. Additional studies were identified from references of included studies and the John Hopkins Centre for Humanitarian Health database. Studies reporting neonates (≤ 28 days old) who tested positive for SARS-CoV-2 by reverse transcriptase PCR (RT-PCR) were included. Descriptive statistics were used to compare mild-moderately ill neonates (non-severe group) with severely-critically ill neonates (severe group). This grouping was based on the World Health Organization’s definition. Continuous variables were analysed using Wilcoxon-Rank Sum Test. Dichotomous or categorical data were analysed with Chi-square and Fisher’s Exact Tests. Quality of the studies were reviewed with Newcastle-Ottawa Scale and Murad Tool.ResultsSixty-seven studies were included out of 199 full text articles screened. Studies comprised of case reports, case series or cohort studies. Of ninety-nine neonates with COVID-19 infection, 72 (72.7%) were symptomatic. Amongst the symptomatic neonates, respiratory symptoms were common: shortness of breath (36.1%), nasal symptoms (19.4%), cough (18.1%). Other symptoms included fever (55.6%), feeding problems (31.9%) and gastrointestinal (GI) symptoms (16.7%). Lymphopenia was present in 43.9% (18 of 41 neonates tested). Elevated C-reactive protein was only reported in 13.2% (5 of 38 neonates tested), while 65.4% (34 of 52 neonates) had chest radiographs suggestive of pneumonia. Thirty neonates (30.3%) had severe-critical illness (severe group), while 69 (69.9%) had mild-moderate illness (non-severe group). Compared with the non-severe group, more neonates in the severe group were symptomatic (100% vs 60.9%, p<0.001), had dyspnoea (66.7% vs 14.3%, p<0.001) and abnormal chest radiographic findings (84.6% vs 61.5%, p=0.038). Accordingly, more neonates in the severe group were admitted to the intensive care unit (91.7% vs 41.7%, p<0.001). On the contrary, mild-moderately ill neonates had increased incidence of fever (69.0% vs 36.7%, p=0.006), and GI symptoms (26.2% vs 3.33%, p=0.01). Ten out of 11 of mild-moderately ill neonates displaying GI symptoms did not have dyspnoea. Laboratory findings, duration of hospital stay, birth characteristics and age at COVID-19 diagnoses were similar between these two groups. No mortalities were reported.ConclusionsPrognosis of COVID-19 neonates were favourable. We postulate that GI symptoms alone predict a better prognosis, while GI symptoms with dyspnoea predict a worse prognosis, as observed in adults. However, our studies were of moderate quality, and clinical findings and investigation results were not completely reported. As the pandemic evolves, prospective studies and more systematic reporting of cases will improve our understanding of neonatal COVID-19 and verify utility of symptoms and laboratory tests in predicting the severity of disease.

Human Milk Antibodies Elicited by BNT162b2 Vaccination Target have reduced activity against SARS-CoV-2 Variants of Concern (preprint)

We detected the presence of SARS-CoV-2 specific IgA against all major VOCs in milk out to 6 weeks after D2 of BNT162b2. These likely confer some protection to the breastfed infants, who are ineligible for vaccination and are at risk of severe COVID-19. However, we detected significantly reduced milk IgA binding to VOCs, including the globally dominant Delta variant, suggesting reduced protection for breastfeeding infants. Additionally, these antibodies were significantly reduced by as early as 4-6 weeks after D2.

Codominant IgG and IgA expression with minimal vaccine mRNA in milk of BNT162b2 vaccinees.

Lactating women can produce protective antibodies in their milk after vaccination, which has informed antenatal vaccination programs for diseases such as influenza and pertussis. However, whether SARS-CoV-2-specific antibodies are produced in human milk as a result of COVID-19 vaccination is still unclear. In this study, we show that lactating mothers who received the BNT162b2 vaccine secreted SARS-CoV-2-specific IgA and IgG antibodies into milk, with the most significant increase at 3-7 days post-dose 2. Virus-specific IgG titers were stable out to 4-6 weeks after dose 2. In contrast, SARS-CoV-2-specific IgA levels showed substantial decay. Vaccine mRNA was detected in few milk samples (maximum of 2 ng/ml), indicative of minimal transfer. Additionally, infants who consumed post-vaccination human milk had no reported adverse effects up to 28 days post-ingestion. Our results define the safety and efficacy profiles of the vaccine in this demographic and provide initial evidence for protective immunity conferred by milk-borne SARS-CoV-2-specific antibodies. Taken together, our study supports recommendations for uninterrupted breastfeeding subsequent to mRNA vaccination against COVID-19.

Titres and neutralising capacity of SARS-CoV-2-specific antibodies in human milk: a systematic review.

OBJECTIVE: Synthesise evidence on production of SARS-CoV-2 antibodies in human milk of individuals who had COVID-19, and antibodies' ability to neutralise SARS-CoV-2 infectivity. DESIGN: A systematic review of studies published from 1 December 2019 to 16 February 2021 without study design restrictions. SETTING: Data were sourced from PubMed, MEDLINE, Embase, CNKI, CINAHL and WHO COVID-19 database. Search was also performed through reviewing references of selected articles, Google Scholar and preprint servers. Studies that tested human milk for antibodies to SARS-CoV-2 were included. PATIENTS: Individuals with COVID-19 infection and human milk tested for anti-SARS-CoV-2 neutralising antibodies. MAIN OUTCOME MEASURES: The presence of neutralising antibodies in milk samples provided by individuals with COVID-19 infection. RESULTS: Individual participant data from 161 persons (14 studies) were extracted and re-pooled. Milk from 133 (82.6%) individuals demonstrated the presence of anti-SARS-CoV-2 immunoglobulin A (IgA), IgM and/or IgG. Illness severity data were available in 146 individuals; 5 (3.4%) had severe disease, 128 (87.7%) had mild disease, while 13 (8.9%) were asymptomatic. Presence of neutralising antibodies in milk from 20 (41.7%) of 48 individuals neutralised SARS-CoV-2 infectivity in vitro. Neutralising capacity of antibodies was lost after Holder pasteurisation but preserved after high-pressure pasteurisation. CONCLUSION: Human milk of lactating individuals after COVID-19 infection contains anti-SARS-CoV-2-specific IgG, IgM and/or IgA, even after mild or asymptomatic infection. Current evidence demonstrates that these antibodies can neutralise SARS-CoV-2 virus in vitro. Holder pasteurisation deactivates SARS-CoV-2-specific IgA, while high-pressure pasteurisation preserves the SARS-CoV-2-specific IgA function.

BNT162b2 vaccination induces SARS-CoV-2 specific antibody secretion into human milk with minimal transfer of vaccine mRNA (preprint)

ImportanceTo examine the impact of SARS-CoV-2 vaccination of lactating mothers on human milk Objective(1) To quantify SARS-CoV-2-specific immunoglobulin A (IgA) and immunoglobulin G (IgG) in human milk of lactating mothers who received the BNT162b2 vaccine, with reference to a cohort convalescent from antenatal COVID-19, and healthy lactating mothers. (2) To detect and quantify vaccine mRNA in human milk after BNT162b2 vaccination. DesignGestational Immunity For Transfer 2 (GIFT-2) is a prospective cohort study of lactating mothers who were due to receive two doses of BNT162b2 vaccine, recruited between 5th February 2021 and 9th February 2021. SettingLactating healthcare workers living in Singapore ParticipantsConvenience sample of ten lactating healthcare workers. Human milk samples were collected at four time points: pre-vaccination, 1-3 days after dose one, 7-10 days after dose one, and 3-7 days after dose two of the BNT162b2 vaccine. ExposureTwo doses of the BNT162b2 vaccine 21 days apart. Main Outcome and Measure(i) SARS-CoV-2-specific IgA and IgG in human milk of lactating mothers who received BNT162b2 vaccine, (ii) Detection and quantification of vaccine mRNA in human milk after BNT162b2 vaccination. ResultsTen lactating healthcare workers aged 32.5 years (range 29 - 42) were recruited, with 40 human milk samples collected and analysed. SARS-CoV-2-specific IgA was predominant in human milk of lactating mothers who received BNT162b2 vaccine. The sharpest rise in antibody production was 3 -7 days after dose two of the BNT162b2 vaccine, with medians of 1110 picomolar of anti-SARS-CoV-2 spike and 374 picomolar of anti-Receptor Binding Domain IgA. Vaccine mRNA was detected only on rare occasions, at a maximum concentration of 2 ng/mL. Conclusions and RelevanceIn this cohort of ten lactating mothers following BNT162b2 vaccination, nine (90%) produced SARS-CoV-2 IgA, and ten (100%) produced IgG in human milk with minimal amounts of vaccine mRNA. Lactating individuals should continue breastfeeding in an uninterrupted manner after receiving mRNA vaccination for SARS-CoV-2. Trial RegistrationRegistered at clinicaltrials.gov (NCT04802278). Key PointsO_ST_ABSQuestionC_ST_ABSDoes BNT162b2 (i) induce the production and secretion of SARS-CoV-2 specific antibodies into human milk, and/or (ii) get secreted into human milk? FindingsIn this cohort that included ten lactating healthcare workers following BNT162b2 vaccination, 90% produced SARS-CoV-2 immunoglobulin A, and 100% produced immunoglobulin G in human milk, with minimal amounts of vaccine mRNA transfer. MeaningLactating individuals should continue breastfeeding in an uninterrupted manner after receiving SARS-CoV-2 mRNA vaccination.

Guidance for the clinical management of infants born to mothers with suspected/confirmed COVID-19 in Singapore.

In this paper, we provide guidance to clinicians who care for infants born to mothers with suspected/confirmed COVID-19 during this current pandemic. We reviewed available literature and international guidelines based on the following themes: delivery room management; infection control and prevention strategies; neonatal severe acute respiratory syndrome coronavirus 2 testing; breastfeeding and breastmilk feeding; rooming-in of mother-infant; respiratory support precautions; visiting procedures; de-isolation and discharge of infant; outpatient clinic attendance; transport of infant; and training of healthcare staff. This guidance for clinical care was proposed and contextualised for the local setting via consensus by members of this workgroup and was based on evidence available as of 31 July 2020, and may change as new evidence emerges.

Breastfeeding in COVID-19: A Pragmatic Approach.

The novel coronavirus disease 2019 (COVID-19) pandemic has resulted in changes to perinatal and neonatal care, concentrating on minimizing risks of transmission to the newborn and health care staff while ensuring medical care is not compromised for both mother and infant. Current recommendations on infant care and feeding when mother has COVID-19 ranges from mother-infant separation and avoidance of human milk feeding, to initiation of early skin-to-skin contact and direct breastfeeding. Health care providers fearing risks of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) maternal-infant transmission may veer toward restricted breastfeeding practices. We reviewed guidelines and published literature and propose three options for infant feeding depending on various scenarios. Option A involves direct breastfeeding with the infant being cared for by the mother or caregiver. In option B, the infant is cared for by another caregiver and receives mother's expressed milk. In the third option, the infant is not breastfed directly and does not receive mother's expressed milk. We recommend joint decision making by parents and the health care team. This decision is also flexible as situation changes. We also provide a framework for counseling mothers on these options using a visual aid and a corresponding structured training program for health care providers. Future research questions are also proposed. We conclude that evidence and knowledge about COVID-19 and breastfeeding are still evolving. Our options can provide a quick and flexible reference guide that can be adapted to local needs. KEY POINTS: · SARS-CoV-2 is unlikely transmitted via human milk.. · A shared decision making on infant feeding is the preferred approach.. · Mothers can safely breastfeed with appropriate infection control measures..