Babies with Zika-linked defects at greater risk of death, study finds

A team of researchers is calling for greater protection of women — particularly those who are pregnant or of child-bearing age — from mosquitoes carrying the Zika virus, after a new study has found that babies born with congenital defects due to infection with the virus are at greater risk of dying in their first three years.

These babies are more than 11 times at greater risk of dying during their first three years of life than those born without the congenital Zika syndrome, according to the study published Wednesday in The New England Journal of Medicine.

The study was based on data of over 11 million babies born in Brazil between 2015 and 2018. The country was the center of a Zika outbreak in 2015 that drew concerns as health authorities saw an increase in congenital anomalies among newborns during this period. In 2016, the Lancet published a study showing links between Zika virus infection and microcephaly, a condition in which the baby’s head is much smaller due to the abnormal development of the brain, among newborns.

But not much is known about the survival of babies born with these birth defects associated with Zika infection — also called congenital Zika syndrome.

“Data on mortality associated with congenital zika syndrome is scarce,” Dr. Enny Paixao Cruz, assistant professor at the London School of Hygiene & Tropical Medicine and one of the study authors, told Devex in an email.

She said there were two studies that estimated the mortality risk of babies with the syndrome, but only during their first four weeks of life. Their study went further by extending the period of follow up for three years, and compared the babies’ survival with babies born without congenital Zika syndrome.

What they found was that of the more than 11 million babies born between 2015 and 2018, 3,308 were born with “confirmed or probable” congenital Zika syndrome. Of this number, 398 or 12% died during the study period, and 163 died during their neonatal period, said Paixao Cruz. In comparison, only 1% of the rest of the babies born without congenital Zika syndrome died during the same period.

“We do not know the survival chance of children with CZS after the first three years, but we will continue to investigate those affected children's long-term outcomes,” she said.

With the study findings, the authors called for better protection of women against the Zika virus, and early interventions for children at high risk of being born with congenital Zika syndrome.

To date, there are no vaccines that protect against Zika. But Paixao Cruz said mosquito bites can be avoided with the use of repellents.

“And it is important to remember that zika can be sexually transmitted too. Therefore condom [use] is also a way to prevent the disease,” she said.