When a baby is born its immune system is not yet fully functional so, as they leave the protected environment of the womb and enter the outside world, they become increasingly vulnerable to potentially life-threatening infectious diseases^.1 In the UK, we’re fortunate to have a well-established childhood vaccination programme, with most babies receiving their first vaccine when they’re just a few weeks old.² As one of the greatest advances in global health, it’s estimated that childhood vaccines save up to 3 million children across the world each year by working with their body’s natural defences to reduce the risk of infection and fight against some of the most prevalent diseases.^3,4 

However, to help bridge the gap from birth to vaccination, there are also some natural processes at play which help to better protect babies from the day they are born. 

A mother’s instinct to protect her baby starts within the first few weeks of pregnancy, with her body kicking into action through a process known as passive immunity.⁵ At this early stage, a pregnant woman will pass vital disease-fighting molecules, called immunoglobulin G or IgG, through the placenta to the unborn foetus.⁵ This sharing of antibodies continues throughout the rest of the pregnancy, offering critical protection to help the newborn to fight off any potential infections throughout their first few weeks.⁶ Before the baby receives any of its childhood vaccinations and as its own immune system starts to mature, these maternal antibodies offer an additional blanket of protection through one of the most vulnerable stages of life.

The mother-to-foetus antibody transfer is one of many fascinating processes that a woman’s body carries out to help her baby thrive after birth. However, as shown in the graphic below, a pregnant woman needs to have acquired disease-specific antibodies to be able pass immune protection on to her baby – either through past exposure to a pathogen, such as a virus or bacteria, or by vaccination.⁷ Receiving the recommended vaccinations during pregnancy will help to both protect the mother and ensure she is able to pass sufficient antibodies on to her baby whilst it is still in the womb.^2,5

Maternal vaccination is a powerful tool to help tackle some of the major causes of infant mortality.⁵ Yet with recent estimates suggesting around 6,500 infant deaths every day from preventable infectious diseases,⁸ there is clearly still a lot of work that needs to be done. Scientists are leveraging years of scientific expertise in vaccine discovery and development to explore new areas in which the diseases that affect very young children could be prevented, helping to reduce childhood disease and fatality and give newborns the best possible start at life. 

References

1. British Society for Immunology. Neonatal Immunology. Last accessed March 2023.

2. NHS. NHS Vaccinations and When to Have Them. Last accessed March 2023.

3. UNICEF. Immunization. Last accessed March 2023.

4. British Society for Immunology. How do vaccines work?. Lass accessed March 2023.

5. Clements, T. et all (2020). Update on Transplacental Transfer of IgG Subclasses: Impact of Maternal and Fetal Factors. Frontiers in Immunology, 11:1920. Last accessed March 2023.

6. NHS. How Long Do Babies Carry Their Mother's Immunity?. Last accessed March 2023.

7. Saso A and Kampmann B (2020). Maternal Immunization: Nature Meets Nurture. Frontiers in Microbiology, 11:1499. Last accessed March 2023.

8. World Health Organisation (WHO). Children: improving survival and well-being. Last accessed March 2023.