The power of vaccinating pregnant women

By Lord Ara Darzi
Institute of Global Health, Imperial College London

image copyrightThinkstock
image captionPregnant women are offered vaccination against whooping cough

Vaccinating pregnant women is crucial, and a way of plugging the "immunisation loophole" and protecting their unborn babies.

In 2012, a nationwide outbreak of whooping cough swept across the UK.

Almost 12,000 people were struck down by the highly infectious disease, which is marked by paroxysmal coughing - accompanied in some cases by the distinctive "whoop" - and can cause severe complications and death.

Newborn babies are especially vulnerable, and, in the three years from 2012 to 2014, a total of 24 babies died under the age of three months old. Thousands more were admitted to hospital.

The sudden upsurge came after more than a decade in which the number of cases had remained in the hundreds.

It proved, in tragic fashion, the vital importance of vaccinating the mother to protect her soon-to-be-born child.

For although whooping cough (known by the medical term pertussis) is a vaccine-preventable disease, the vaccine does not work in those most at risk - babies under three months.

Their developing immune systems are unable to mount the protective response that vaccination in an older infant will trigger.

MMR scare

This is immunisation's loophole. But there is a way of plugging it. Instead of vaccinating the child, vaccinate the mother.

The antibodies she creates to the disease are then passed via the placenta to the baby, who is protected after birth.

In the late 1970s and early 1980s, up to 70,000 cases of pertussis were recorded each year in the UK.

The numbers soared after a scare about the safety of the vaccine in 1975 linked it, wrongly, to brain damage, which led to a fall in vaccination rates.

Years later, the scare over the MMR vaccine, which was wrongly linked to autism in the late 1990s, had a similar effect.

image copyrightScience Photo Library
image captionBabies are given the pertussis jab when they are a few months old

To ensure protection for newborns via their mothers, all pregnant women in the UK have been offered the pertussis vaccine in the third trimester of pregnancy since 2012, but many resist because of misplaced fears about its safety.

Today, it is combined with vaccines against polio, diphtheria and tetanus - diseases that have been virtually eliminated from the UK but could make a comeback.

The combined vaccine, called Boostrix IPV, had a take up rate in England of 62% in 2014.

The vital contribution of maternal vaccination is seen more dramatically elsewhere around the globe.

In 2008, there were an estimated 16 million cases of pertussis worldwide and 195,000 deaths.

In those countries where maternal vaccination programmes have been introduced, deaths have dropped sharply.

Flu vaccination is also recommended for women during pregnancy to protect themselves, their unborn child and the newborn in its first few months.

A woman's immune system is weakened naturally during pregnancy, to prevent her body rejecting the baby.

But this makes her more vulnerable to infections such as flu.

Vaccination of the mother during pregnancy also confers protection on her child and has been shown to reduce cases of flu in newborns by 63%.

'Vigorous support' needed

Maternal vaccination against flu was recommended as far back as 1960 in the US and in 2005 by the World Health Organization (WHO).

In England, it was first recommended for pregnant women during the swine flu pandemic of 2009.

But take-up rates for the vaccine are low, at 44% in England in 2015.

The biggest maternal vaccination success story - on a global scale - is against tetanus, the deadly infection marked by muscle spasms caused by a bacterium in the soil getting into a wound.

More than one million people died each year from tetanus in the 1980s, about three-quarters of them infants in the first month of life.

Today, the toll of neonatal deaths has been reduced by over 90% and maternal and neonatal tetanus has been eliminated from all but 22 countries.

In a paper summarising these findings, published in the US Journal Health Affairs and based on a policy briefing presented to the World Innovation Summit for Health (WISH) in Doha, Mark Steedman, of the Institute of Global Health Innovation, and I, together with colleagues, call on governments to recognise the extraordinary benefits achieved by maternal vaccination and to focus efforts on extending its reach.

Millions of mothers and newborns still die each year from infectious diseases, and a number of other vaccines are in the pipeline that could be used in pregnant women.

One study published in the US this month showed that in one health system (Geisinger in Danville, Pennsylvania) 70% of pregnant women were vaccinated against flu and 76% against pertussis, tetanus and diphtheria - much higher than the figures for the UK (44 and 62%).

Patient education and physician recommendation were the key factors, according to the researchers.

Ministers must ensure these are vigorously supported and pregnant women urged to seek protection for themselves and their unborn children.

The power of vaccination in pregnancy is a message that should be broadcast far and wide.

Lord Darzi is a surgeon, director of The Institute of Global Health Innovation, and executive chairman of the World Innovation Summit for Health, an initiative of the Qatar Foundation. He was a Labour health minister 2007-09.

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