The way you were born could decide your response to life-saving vaccine!

The way a newborn is delivered could change the way their immune system later responds to life-saving vaccine.

A new study from China suggests the route from womb to world, whether vaginal or surgical, can impact how well the measles vaccine works. Children born via cesarean section need that second jab more than most, researchers found. Without that booster, the vaccine is at a higher risk of failing.

The analysis was conducted by scientists at the University of Cambridge and Fudan University in China and includes data from 1,505 mother-infant pairs in China.

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Typically, about 5 percent of children given the first dose of the measles vaccine under the age of 1 do not show an antibody response. Between 2013 and 2018, however, babies born via C-section in China were 2.56 times more likely to experience measles vaccine failure than those born vaginally. Luckily, the second measles jab made up for that failure, triggering a belated and "robust immune response".

But that lag is important to know about, as it can help inform effective vaccine policies.

In 2021, millions of children around the world missed their measles booster - a record number that puts herd immunity in numerous nations at a dangerous tipping point. A lot of children don't end up having their second measles jab, which is dangerous for them as individuals and for the wider population.

Infants born by C-section are the ones scientists really want to be following up to make sure they get their second measles jab, because their first jab is much more likely to fail.

Measles is a viral respiratory disease of imminent threat and one of the most contagious diseases we know of. The vaccine is all we have to reign it in, and it requires at least a 95 percent vaccination rate to achieve herd immunity in a population.

Why is this?

Children born via C-section, as opposed to those born vaginally, have a slightly higher likelihood of some immune disorders, and while scientists still cannot work out why that is, there's every reason to find the reason out.

In 2022, a study linked C-sections to lower antibody  responses after meningococcal and pneumococcal vaccines. In the research, babies born vaginally had double the level of protective antibodies  after receiving the jabs.

Scientists theorized then that babies born via C-section are not 'seeded' with the same important germs from their mother's vagina, and these can have a stimulating effect on a newly formed immune system.

However, that is just a theory right now. While C-section babies do show a different range of bacteria in their guts compared to those born vaginally, other studies suggest the differences disappear after about 9 months.

Since 2000, the rate of C-sections has doubled worldwide. The surgery now accounts for about 20 percent of births globally, and up to half of all births in some countries.

It is crucial for public health that we know how the popular procedure is impacting the immunity of the next generation.

Source: https://www.nature.com/articles/s41564-024-01694-x