With the U.S. coronavirus vaccination rate among adults slowing and attention turning to the young, a new survey by researchers from Northeastern, Harvard, Northwestern, and Rutgers finds that mothers were significantly more reluctant to vaccinate their children than fathers, with the highest resistance coming from mothers under 36 years old.

Twenty-seven percent of mothers were opposed to vaccines compared to 11 percent of fathers. Resistance was highest (31 percent) among moms between the ages of 18-35 who say they are “extremely unlikely” to inoculate their kids compared to 25 percent of older moms who oppose vaccinations.

The findings come as U.S. health authorities are trying to get enough people vaccinated against SARS-CoV-2, the coronavirus that causes COVID-19, to achieve herd immunity. President Biden has set a new vaccination goal to deliver at least one dose to 70 percent of U.S. adults by July 4.

The survey found that among fathers, age appears to have little impact on vaccine hesitancy and resistance, with nearly two-thirds (64 percent) reporting they are likely to vaccinate their young.

Researchers didn’t ask respondents why they were for or against their children getting vaccinated. But resistance could negatively impact the nation’s overall vaccination rate since mothers tend to hold more sway over their children’s healthcare than fathers.

Those younger than 21 make up about 25 percent of the U.S. population. If many of them get vaccinated, it raises the chance of herd immunity. But the survey found increasing pockets of hesitancy or stiff resistance among parents without a college degree or earning less than $25,000 a year. 

The findings “suggest that the ceiling for the vaccination rate of children will be a lot lower for certain demographics,” says David Lazer, university distinguished professor of political science and computer sciences at Northeastern and one of the researchers who conducted the study. 

The survey of nearly 22,000 U.S. residents was conducted between April 1 and May 3, ahead of the Food and Drug Administration’s expected authorization early next week of the Pfizer vaccine for adolescents ages 12 to 15. Some mothers who feel strongly against vaccinations are likely to have children in that age range.

The number of adults getting their first dose of the vaccine is declining in at least 47 out of 50 U.S. states, according to data from the Centers for Disease Control and Prevention. From mid-to-late April, 47 states and the District of Columbia showed a downward trend in first doses administered. And on Monday, the United States recorded its lowest one-day total of doses administered since February.

Biden’s goal of delivering at least one dose to 70 percent of U.S. adults by July 4 includes fully vaccinating 160 million adults by Independence Day.

In advance of federal approval of the Pfizer vaccine for 12-to-15-year-olds, the White House is also developing plans to speed vaccinations to that age group.

“I want American parents to know that if that announcement comes, we are ready to move immediately to make about 20,000 pharmacy sites across the country ready to vaccinate those adolescents as soon as the FDA grants its OK,” the president said at the White House Tuesday.

He has challenged states to administer at least one dose to individuals in that particular age bracket by July 4 and work to deliver doses to pediatricians and others, with the hope that extending vaccinations to teens will speed up the country’s reduced coronavirus caseload and allow schools to reopen with minimal disruptions this fall.

Those in favor of compulsory school vaccinations grew slightly from 54 percent to 58 percent nationally between February and April, the survey found. However, among Republicans, support was virtually unchanged. There was a slight uptick among Democrats (from 72 percent to 76 percent), while Republican support was static at roughly 38 percent.

Growth in vaccination support was fairly even among rural, suburban, and urban residents, though support continues to be higher in denser areas: 66 percent for urban residents, 56 percent for suburbanites, and 49 percent for rural residents.

“This is significant because school policy is generally set on a state and local level,” researchers wrote in the study. “We may be more likely to see vaccine mandates implemented in urban areas and Democratic-leaning states and school districts than in more rural and Republican states.”

Last week, Connecticut became the sixth state to no longer allow a religious exemption from childhood immunization requirements for schools, colleges, and day care facilities. Connecticut students in kindergarten and older with an existing religious exemption will be grandfathered. The state’s medical exemption will remain in place.

The other states without religious exemptions for vaccines are California, New York, West Virginia, Mississippi, and Maine, according to the National Conference of State Legislatures.

“There will likely be more people pushing for removal or tightening of religious exemptions because otherwise you do get large clusters of vulnerable people, in particular school systems, and that creates the risk of outbreak,” says Northeastern’s Lazer.

While pandemic-related deaths among children are low, there are societal benefits to vaccinating children, he adds.

“We don’t know what the long-term effects from the coronavirus may be on children. And by getting them vaccinated, the broader population benefits because you’re protecting parents and grandparents. So there are benefits to children both in the short run and in the longer run.”

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