Unlike other diseases that spread via the blood, such as HIV and hepatitis B, the risk of infection during pregnancy is low for hepatitis C. Transmission of hepatitis C from an infected mother to an infant is uncommon. About 2-8 percent of infants born to mothers with this condition get the disease—an incidence that piqued the interest of researchers at Sweden’s Karolinska Institute who may have just found the explanation: Adaptations in the infant’s immune system. This discovery can pave the way for developing new and improved treatments for hepatitis C.
The risk of pregnant women passing on hepatitis C to an infant is low and only happens at the time of birth. To investigate this low infection risk, the researchers conducted a study with 55 pregnant women, of which 40 had an active hepatitis C infection while the rest had antibodies from a previous hepatitis C infection. The babies born to the women with active infection were all considered to have been exposed to the virus. After the women gave birth, it was found that only three of the 40 infants developed hepatitis C.
Analyzing the results, Dr. Niklas Björkström of Karolinska Institute shared: “The immune system of the healthy babies shows similar changes to that in babies infected with hepatitis C. This could suggest that the immune cells have encountered the virus in the womb and managed to eliminate it before birth.”
Simply put: The infant’s immune system may have already destroyed the virus before birth.
The infants in the study were monitored and tested for 18 months. To add comparable data, information from 18 infants who were infected with hepatitis C at birth was added.
In a typical setting, it takes about 18 months after birth to test an infant for hepatitis C. This is because the infant will automatically get the mother’s antibodies, and it takes this long before the infant’s body can clear out the mother’s antibodies.
Of note, hepatitis C has not been found to cause any problems during pregnancy. No research evidence shows that hepatitis C can be transmitted through breastfeeding, thus breastfeeding by women living with hepatitis C is generally considered safe. While the risk of hepatitis C transmission from mother to child is low, it does get higher if a mother is also infected with HIV.
The study showed that both the babies born with an infection and those who had been exposed to the virus by an infected mother had similar changes in their adaptive immune system. All infants showed clear adaptations of the B lymphocytes, the role of which is to produce antibodies able to discover and identify alien microbes, such as viruses, bacteria, and parasites.
“A possible explanation is that most babies exposed to the virus in utero manage to deal with it, which we can later see by the B lymphocytes,” said Dr. Björkström. “One interesting hypothesis is that these cells can contain novel information that we can use to protect ourselves against hepatitis C in the future,” he added, stressing the importance of their new findings in improving our understanding of immunity and lasting protection against the hepatitis C virus and in developing new hepatitis treatments.
Hepatitis C affects over 70 million people across the globe. Without treatment, hepatitis infection can lead to liver cirrhosis and liver cancer. No vaccine has been developed to protect people against hepatitis C. As such, in the United States, the CDC recommends one-time hepatitis C testing of all adults 18 years and older and all pregnant women during every pregnancy. People with risk factors, including people who inject drugs, are encouraged to get tested regularly. ADRLF can’t echo this CDC recommendation enough: Screen. Vaccinate. Don’t Hesitate.
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