When moms on welfare work, their children may be somewhat less likely to get their vaccinations on time, a new study suggests.

Researchers found that among 457 low-income children they followed, rates of on-time vaccination were higher when families were receiving welfare than when they were not.

But when mothers on welfare were also in the workforce, their children were less likely to be up-to-date in immunizations.

When moms on welfare worked, 53.5 percent of their children’s vaccine doses were given on time. That compared with 59 percent when mothers did not work, researchers report in the journal Pediatrics.

It’s not clear why the difference existed. And it’s possible that mothers’ work, itself, is not the reason, according to lead researcher Min-Woong Sohn, of the Institute for Healthcare Studies at Northwestern University in Chicago.

But, he told Reuters Health, “what we suspect is that, when mothers worked, they didn’t have time to take their child to the pediatrician.”

Women on welfare, Sohn noted, are likely to have jobs that are low-paying and offer little flexibility - with no paid time off, for example. So they may have a tougher time getting their kids to routine doctor visits than other working moms do, Sohn said.

The U.S. welfare reform of the 1990s reshaped how the program operates.

Mothers with young children were required to work, or take part in job training, to receive welfare benefits. States can exempt mothers from that rule during a child’s first year of life.

But that year still counts toward a family’s lifetime welfare limit, which is five years. So some mothers may choose to work despite the exemption.

HOW TO BOOST RATES

A potential way to boost vaccination rates, according to Sohn, could be for states to exclude that one-year exemption from counting toward a family’s lifetime welfare limit.

Another, Sohn said, would be for states to target particularly “high-risk” families in their efforts to get all kids up-to-date in recommended vaccinations.

Based on this study, that would include children on welfare with working moms, and children whose moms are out of work and not eligible for welfare.

Kids in that latter group had the lowest rate of on-time vaccinations. Just under 45 percent of their shots were given on schedule, the study found.

“That’s the highest-risk group,” Sohn said, “and it’s a group we really need to be paying attention to.”

Low-income children can get free vaccines from doctors participating in the federal government’s Vaccines For Children program (though the doctor’s visit is not free of charge). But families need to be aware that the program exists.

The current findings are based on a sampling of Illinois families who were receiving welfare in 1998. Their young children’s vaccination rates were followed through 2004.

Overall, 56 percent of the children’s vaccine doses were given on time. That rate was highest - about 60 percent - when mothers were either on welfare and not working, or were not on welfare but were working.

That latter finding, according to Sohn, may reflect the fact that working families no longer on welfare were probably doing better. More mothers, for example, may have been able to afford a day off from work to go to the pediatrician’s office.

Illinois is one of a number of U.S. states that exempts mothers with babies younger than one year from the work requirement. But as it stands, that year counts toward the welfare time limit.

SOURCE:  Pediatrics, online November 28, 2011.