The strategy, known as cocooning, is meant to block diseases from reaching the infant in the first place and is backed by the U.S. Centers for Disease Control and Prevention.

But earlier this month, Canadian government researchers suggested that at least for whooping cough, a major infectious disease worldwide, cocooning comes with a hefty price tag.

They estimated that to prevent one infant death from the disease in Quebec or British Columbia, at least one million parents would have to be vaccinated -- at a cost of some 20 Canadian dollars per shot.

"This program appears inefficient," said Dr. Danuta Skowronski, of the British Columbia Center for Disease Control in Vancouver.

"In fact, the criteria for this to be successful are almost impossible," she told Reuters Health. "We're not saying that babies are not important -- of course they are -- but we have to be wise about how we use our finite resources."

The new American Academy of Pediatrics' report on cocooning, released in the journal Pediatrics, is not directly recommending that pediatricians start offering parents shots -- a practice that has been controversial.

"What it says is, if you choose to do it, this is ok," said the AAP's Dr. Herschel R. Lessin, who worked on the report. "They give flu shots in airports and pharmacies. There is really no reason why a licensed doctor can't give them also."

SHIELDING THE BABY

Lessin said the main focus is on flu shots and the TDaP vaccine, which protects against tetanus, diphtheria and whooping cough (pertussis).

There is already a national U.S. mandate to give these vaccines to everybody, he added, including pregnant women. But babies have to be at least six weeks old to get the TDaP vaccine and six months old to get a flu shot.

In the meantime, their only protection is through antibodies they get from their mother in the womb and in breast milk if she has been vaccinated or has natural immunity against the infections.

Lessin said that because not all pregnant women get vaccinated, cocooning is still a reasonable strategy to shield infants.

People with whooping cough typically cough uncontrollably and may have trouble breathing. The disease is especially dangerous for newborns, whose immune systems are still not fully mature.

According to the CDC, more than half of babies under one year who get whooping cough need to go to the hospital.

While rates of the infection have dropped fast over the past half century, they have begun to climb again over the past few years. About one in 1,000 U.S. infants caught the pertussis bug last year, the CDC says, although these are only the reported cases.

"The goal here is to get everyone immunized," said Lessin. "As pediatricians, we think immunization is the greatest thing in the history of mankind."

Because it's a "hassle" for pediatricians to bill parents' insurance for the shots, he said the most practical thing is to have people pay out of pocket for the vaccines -- in the case of a flu shot, around $30.

LACK OF EVIDENCE

Lessin acknowledged that there isn't much evidence on how effective cocooning really is.

"It's a relatively new concept," he said. "I don't know that anyone has looked at whether it works."

The Canadian study, published in the journal Clinical Infectious Diseases, takes a stab at that, although it's based on calculations instead of an actual experiment.

From past research, Skowronski and her colleagues estimated that whooping cough in infants could be blamed on parents passing the disease along some 35 percent of the time.

Given rates of the disease in Quebec and British Columbia from 2005 to 2009, which were about the same as in the U.S., the researchers found that to prevent one baby from being hospitalized, between 10,000 and 20,000 people would need to be vaccinated.

To prevent a baby from landing in an intensive care unit, the number rose to about 100,000. To stave off a death, 1 million parents would have to get the vaccine -- at a total price of some 20 million Canadian dollars.

"Basically what we're calling for is that regions that are considering the cocoon program take into account what the risks are for parents passing pertussis to their infant," said Skowronski.

A 'SUCCESS STORY'

An editorial published along with the Canadian study notes that the results don't necessarily apply to areas with high rates of whooping cough or recent outbreaks.

Dr. C. Mary Healy, who co-wrote the editorial, added that, "in the overall cost of having a baby, the cost of a vaccine is not huge."

Healy, of Texas Children's Hospital's Center for Vaccine Awareness and Research in Houston, helped launched a campaign in 2008 to vaccinate new mothers before they left the hospital. In 2009, it was expanded to any family members who would be near the baby.

"In Houston, what drove us was that nationally there was an unacceptable level of death," she said.

The U.S. CDC has called the program a "success story."

Dr. Tom Clark, a researcher at the CDC, told Reuters Health the government published an updated cocooning recommendation in October.

It now urges expectant mothers to get the vaccine against whooping cough late in pregnancy, and recommends that other people in contact with the baby get vaccinated as well.

Healy said the main problem is access. Not all fathers go to prenatal visits, for instance, and not all grandparents or people coming to visit the baby are accessible.

She acknowledged that money is not a concern with her program.

"Our program is funded from foundation grants and donated vaccines," said Healy. "We don't have cost barriers."

SOURCES: bit.ly/cxXOG Pediatrics, online December 26, 2011, and bit.ly/unGnjD Clinical Infectious Diseases, online December 8, 2011.

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