If the person doing the kissing has the herpes virus.
Mariana Sifrit was rushed to the hospital on July 7—just one week after she was born—after her parents, Nicole and Shane Sifrit, noticed she wasn't eating and wouldn't wake up. Less than two weeks later, Mariana died, CNN reports. She was 18 days old.
The newborn, who fell ill a few hours after her parents' wedding ceremony, had contracted viral meningitis from HSV-1, a condition which causes inflammation of the tissue that covers the brain and the spinal cord. Though this viral form of meningitis is often less severe than bacterial meningitis (most people get better on their own), it hits those with weakened immune systems—like babies younger than 1 month old—especially hard, according to the Centers for Disease Control and Prevention.
If you recognized HSV-1—good eye; it stands for herpes simplex virus, the same bug that causes cold sores. HSV-1 is very common but only rarely does it lead to viral meningitis, per the CDC. Johns Hopkins says that HSV-2 could also cause meningitis in babies; this virus can cause genital herpes and could be passed from mother to infant during childbirth, so some women who've had outbreaks opt to deliver by cesarean section.
In newborns, meningitis from either HSV-1 or HSV-2 could be severe and require hospitalization. "The first two months after a child is born are very critical, as a virus can rapidly spread and cause serious illness in newborns," Tanya Altmann, a pediatrician at Calabasas Pediatrics in California, told CNN.
Though doctors can't be sure exactly what caused Mariana's meningitis, it's believed that she acquired it through a kiss from an infected person—even if they weren't showing symptoms at the time, since the virus remains in the body for life. Both Nicole and Shane tested negative for the HSV-1, the type Mariana had, so it likely came from skin-to-skin contact with another friend or family member. In theory, a kiss on the mouth wouldn't be necessary to transmit the virus; Mariana could have gotten it from touching her mouth with her hand.
"We need to be careful about talking to parents and grandparents about not kissing newborns when they have [the herpes virus], because often the baby has no immunity at all," Yvonne Bryson, a professor of pediatric and infectious diseases at the University of California at Los Angeles, told Tonic in June. Six weeks old is the cutoff point—by then, a baby's immune systems has built up enough so that the risk of a life-threatening infection from a virus like herpes becomes nearly negligible.
Mariana spent the last week or so of her short life at the University of Iowa Children's Hospital, where she suffered from liver damage and multiple organ failure as her condition deteriorated. Mariana died at 8:41 am Tuesday morning.
"In her 18 days of life she made a huge impact on the world, and we hope with Mariana's story we save numerous newborns," Nicole wrote in a Facebook post.
The herpes simplex virus isn't the only cause of viral meningitis: People with the flu, chickenpox, shingles, measles, or mumps could also make a newborn seriously ill. Even people who feel healthy should wash or sanitize their hands before touching a newborn.
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