Antibodies transmitted via breast milk last for 6 months after COVID mRNA vaccination

The virus responsible for the pandemic of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), Coronavirus Disease 2019 (COVID19) has spread rapidly worldwide since its first discovery in December 2019. .. 19. Vaccine development has been accelerated to unprecedented levels, with the earliest vaccines approved for use within a year.

new International Journal of Infectious Diseases The study describes the effects of the COVID-19 vaccine on lactating mothers and links their antibody response to the protection of both newborns and older babies.

study: Serum and Milk SARS-Cov-2 Specific Antibodies After BNT162b2 Vaccine: Long-term Protection from SARS-Cov-2 in Newborns and Older Infants.. Image Credit: 1 Photo / Shutterstock.com

Preface

Pregnant and lactating women were intentionally excluded from clinical trials of the COVID-19 vaccine based on the messenger ribonucleic acid (mRNA) platform. However, animal studies did not show evidence of post-vaccination lactation disorders.

Immediately after the vaccine was deployed, many pregnant and lactating women chose vaccination because of their high risk of exposure to COVID-19. Shortly thereafter, most expert groups determined that the benefits of the COVID-19 vaccine outweighed the risks to these female subsets, and then vaccinated this patient population after discussing the benefits and adverse effects. Recommended to provide.

Early in the COVID-19 pandemic, women with a history of COVID-19 were found to produce anti-SARS-CoV-2 antibodies in breast milk. These antibodies are primarily in the form of secretory immunoglobulin A (sIgA) and were able to neutralize the virus when they invaded the body.

Researchers in the current study examined breast milk and serum samples from lactating health care workers in a single hospital to evaluate antibody profiles after vaccination. In summary, a total of 18 women vaccinated with Pfizer BioNTech BNT162b2 COVID-19 vaccine, 1-36 months after birth, were included in the current study.

Serum and milk samples were collected before, 3 weeks, 3 weeks after the second dose, and 6 months after the second dose.Serum IgG and IgA antibodies against the virus Spike protein It was measured and the ratio was obtained.

In breast milk, sIgA and sIgG were evaluated. These levels were then compared to standard curves obtained by measuring the corresponding antibodies in the breast milk of women who recovered from a natural infection with SARS-CoV-2.

Survey results

Higher anti-spiked IgG and IgA levels were observed in serum at all time points after vaccination and peaked 3 weeks after the second dose. However, 6 months after the second dose, these titers declined. Antibody levels varied less after the second dose compared to the first dose.

Anti-spike IgA levels are increasingly dispersed at each point in time. In fact, the IgA levels in the three samples that showed low antibody responses at all time points were below the cutoff value at the last time point.

In breast milk, sIgG increased after vaccination and had a slight peak 6 months after the second dose. By comparison, sIgA levels were high at the first two points after vaccination and peaked 3 weeks after the second dose. This was similar to the reaction observed with serum. Nevertheless, sIgA levels dropped to near baseline levels by 6 months from the second dose.

Implications

The most common way for newborns to become infected with SARS-CoV-2 is by aerial transmission from an infected mother. Although rare, SARS-CoV-2 has also been confirmed to be vertically transmitted. Importantly, breast milk is not a vehicle of transmission and is not known to contain a culturable virus.

Breast milk protects against respiratory viral infections, including influenza. The most basic protection is mediated by sIgA. It has been shown to be induced against SARS-CoV-2 by spontaneous infection and vaccination of lactating women. However, in the current study, vaccination could not result in an increase in sIgG in breast milk.

Therefore, mucosal immunity is enhanced by repeated doses of the vaccine, thereby inducing SARS-CoV-2, followed by sIgA, the major immune response to IgG. Vaccination elicited a strong immune response in both lactating and non-lactating women. The magnitude of the response to the first dose predicted the final antibody level, even taking into account the decline 6 months after the second dose.

This reduction may reflect the limitations of vaccines given intramuscularly and may not elicit a strong mucosal antibody response. Breast milk IgA is derived from both serum and local mucosa-associated lymphoid tissue (MALT). Therefore, it does not correlate with serum IgA titers.

These levels tend to rise with continued breastfeeding, so the decline in sIg levels over time should be interpreted with caution. Extrapolated from previous studies of other respiratory infections, IgG appears to be an important protecting factor for newborns.

It suggests a similar role in vaccine-induced milk immunity and that beneficial effects may continue for months after anti-COVID-19 vaccination with mRNA preparations... “

Given the higher severity of neonatal SARS-CoV-2 infection compared to older children, it is essential to monitor the immune response to this virus throughout the first year of life. This helps optimize the timing of vaccination and puerperium during pregnancy to maximize protection of both mother and baby from the virus.

Vaccination during late pregnancy or lactation may be most beneficial to newborns as it provides both placental IgG migration and mucosal protection via secretory IgA and IgG antibodies in breast milk. Booster doses can be used to increase the level of protection to prolong the duration of passive immunity in the baby.