Mothers in China are not passing on protective antibodies against measles to their infants, leaving children under 8 months vulnerable to the disease, researchers at the University of Michigan (UM) have found.
Moreover, the level of protective antibodies decreased with age, with almost all infants lacking maternal antibodies at 3 months old.
The study shows that current vaccination programs are not effective in controlling transmission of measles to infants, said Matthew Boulton, senior associate dean for global public health at UM School of Public Health. He suggests the infants or their mothers may need additional protection.
The 2011-2015 study involved 551 infants aged one to eight months old and their mothers from 120 rural villages and urban communities representing each of the 16 geographic districts in Tianjin in northeastern China.
Research has shown that when a pregnancy goes full term and the mother has adequate nutrition, she will typically pass on antibody protection to the fetus if she has been immunized or has had a case of the measles.
The current study showed mothers with a known history of measles provided 1.6 times higher titers, the concentrations of antibodies in the blood, to their infants than those mothers who had no known history with the disease or vaccination; over two-thirds of mothers who were immune to measles were unsure if they had been vaccinated or had disease.
Although infant deaths have decreased by 79 percent since 2000, measles continues to be one of the most infectious diseases in the world, and claimed more than 134,000 lives worldwide in 2015, mostly infants and young children. And a large percentage of measles cases continue to occur in China.
In China, children usually receive the first dose of measles vaccine at 8 months, and the second dose at 18-24 months.
"China has been very successful at immunizing eligible children for measles and for carrying out very large Special Immunization Activities (e.g., National Immunization Days), which have resulted in literally millions of children being vaccinated for measles in a short period of time," Boulton said.
"Despite these successes, measles continues to occur at unacceptably high rates in both young infants and adults, which points to the need for new approaches, including the possibility of launching organized campaigns to immunize young women of reproductive age," Boulton said.
The study was published in the latest issue of Journal of Infectious Diseases.