AuthorisedTherapeutic use (Phase IV)Interventional

A single-center, randomized, single-blind, phase 4 study to evaluate the enhancement of mucosal immunity in infants through maternal vaccination during breastfeeding (MEALAC-01).

This study, called MEALAC-01, is carefully exploring whether giving a measles vaccine to mothers while they are breastfeeding can boost the protection their babies get against measles. The main goal is to measure the amount of special protective substances, called antibodies, in breast milk. Researchers will compare mothers who receive the measles vaccine with those who don't, over a three-month period. They will collect breast milk samples five times during this time to see if more antibodies are passed on, which could help protect the baby. This is an important way to understand how maternal vaccination might help safeguard infants.

At a glance

Status

Authorised

Phase

Therapeutic use (Phase IV)

Sponsor

Universite Libre de Bruxelles

Enrolment target

120

Start

14 Apr 2026

Measles

What is this study about?

MEASURES, MEALAC-01, is a study designed to understand if giving certain vaccines to mothers who are breastfeeding can help protect their babies. You might know that babies get some protection from their mothers during pregnancy, but this study is looking at whether breastfeeding mothers can also pass on extra protection through their milk after their baby is born. The focus here is on protection against measles.

The researchers want to see if mothers who get a measles vaccine while breastfeeding will have more of these protective substances, called 'antibodies,' in their breast milk compared to mothers who haven't had the vaccine. These antibodies are like tiny soldiers that fight off infections. If these antibodies are present in higher amounts, it suggests they could give the baby better protection against measles.

This study is important because measles can be a serious illness, especially for very young babies. Understanding if maternal vaccination during breastfeeding can enhance a baby's immunity (their ability to fight off illness) could lead to new ways to keep babies healthier and safer.

Key takeaways

The study explores if a measles vaccine in breastfeeding mothers boosts baby's protection.
It measures protective antibodies in breast milk over three months.
Participation involves providing breast milk samples and possibly receiving a vaccine.
Aims to find new ways to keep babies safe from measles.
You can withdraw from the study at any time.

Who may be eligible?

This study is looking for mothers who are at least 18 years old and are currently breastfeeding. The study is open to mothers of all backgrounds.

To join, you would need to be in good general health and willing to provide regular breast milk samples and information to the study team. Both mothers who have recently had a measles vaccine and those who haven't would be considered.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you at least 18 years old?
Are you currently breastfeeding?
Are you interested in learning about how vaccines can help protect babies?
Are you willing to make regular visits for breast milk samples over three months?
Are you able to speak and understand English?

Answer every question to see your result.

What does participation involve?

If you decide to take part in this study, you would be involved for about three months. During this time, the main activity will be providing samples of your breast milk. You would be asked to give these samples five times over the three-month period. This allows the researchers to track any changes in your breast milk over time.

There might be some brief visits to the study clinic to provide these samples and for the study team to gather some health information from you. You might also have a measles, mumps, and rubella (MMR) vaccine during the study if you haven't recently received one, depending on which group you're in. The study team will explain everything clearly before you agree to participate.

Potential risks and benefits

Taking part in a study like this can have potential benefits, such as contributing to medical knowledge that could help protect babies in the future. You might also gain a better understanding of your own health and immunity. As with any medical study, there can be some minor risks. If you receive the vaccine as part of the study, you might experience mild side effects like a sore arm or a slight fever, similar to any routine vaccine. The study team will explain all known risks. You are always free to leave the study at any time, for any reason, without it affecting your medical care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Belgium

Common questions

What is measles and why is it serious?

Measles is a very contagious illness that can cause a rash, fever, and cough. It can be serious, especially for young children, leading to problems like ear infections, pneumonia, or even more severe complications.

What are 'antibodies'?

Antibodies are special proteins made by your body's immune system. They help to recognise and fight off germs like viruses and bacteria, protecting you from illnesses.

Will my baby get extra protection from the vaccine if I join?

That's exactly what the study is trying to find out! Researchers are investigating if vaccinated mothers pass more protective antibodies through breast milk. They hope to understand if this can offer better protection for babies.

Do I have to get a vaccine if I join?

Some mothers in the study will receive the measles vaccine, and some will not. The study team will discuss with you which group you might be in and what's involved.

Who is running this study?

This study, called MEALAC-01, is being run by a research team at a single hospital or medical centre. It's a phase 4 study, meaning it's looking at the effects of a licensed vaccine in a specific new way.