03/03/2015 05:50 EST | Updated 05/03/2015 05:59 EDT

Delaying Childhood Vaccinations Can Be Just as Risky as Not Getting Them At All

In Canada, health care is a provincial responsibility. So, the provincial ministries of health draw up the vaccination schedules. You'll find slight variations in the different schedules. Some provinces may adopt new vaccines sooner than others. Or, a vaccine may target a different strain of a particular bug, reflecting what's circulating locally.

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Brave little girl receiving injection or vaccine with a smile

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QUESTION: Please don't get me wrong. I am not one of those crazy anti-vaxxer parents opposed to vaccinations. I want my child to get the shots, but there are just so many of them. At some appointments, the doctor gives more than one needle which makes my daughter really upset. A friend recently gave me a copy of The Vaccine Book: Making the Right Decision for Your Child. It's by Dr. Robert Sears, an American pediatrician, who says it's okay to spread out the shots over a longer period of time. He is a real doctor and seems to know what he's writing about. What do you think?

ANSWER: The short answer is that you should stick to the regular childhood immunization schedule for your province. But I'm sure you would like a more detailed explanation. So here goes:

Dr. Sears practices medicine in southern California, which has become one of the hotbeds of the anti-vaccine movement. He has said that he wrote the book to provide a middle path for parents like you who feel that their kids are getting too many shots too soon. He presents his alternative vaccine schedule as a reasonable compromise. It delays shots and spaces them further apart. Some vaccines, he suggests, could be dropped entirely. For instance, he concludes the polio vaccine isn't necessary because American children no longer come into contact with the virus that causes the potentially crippling disease.

"My alternative schedule is simply an option for parents who ... just want to do it at a slower pace," Dr. Sears wrote in an online blog defending his book. "I worry that if doctors don't offer an option like this, some patients will go unvaccinated, and that is not good. I believe this schedule will increase vaccination rates among non-vaccinating families."

Dr. Sears -- who likes to go by the folksy title of "Dr. Bob" -- has attracted a wide following among vaccine-hesitant parents. His book has reportedly sold more than 180,000 copies since it was first published in 2007.

Although he may be very well meaning, Dr. Sears is not a vaccine expert, nor is he involved in vaccine research. His so-called "alternative" schedule isn't based on any studies or scientific evidence. He simply made it up.

Equally worrisome, his book contains numerous errors, outdated information and misleading comments, according to experts who have spent their professional careers studying the human immune system.

"He is trying to find some middle ground, but what he does is validate the parents' ill-founded concerns that children just can't handle all those vaccines at once," says Dr. Paul Offit, the Chief of the Division of Infectious Diseases and the Director of the Vaccine Education Center at the Children's Hospital of Philadelphia.

By suggesting that certain vaccines can be postponed, Dr. Sears "is increasing the period of time during which children are susceptible to vaccine-preventable diseases with no benefit," says Dr. Offit.

In Canada, health care is a provincial responsibility. So, the provincial ministries of health draw up the vaccination schedules. You'll find slight variations in the different schedules. Some provinces may adopt new vaccines sooner than others. Or, a vaccine may target a different strain of a particular bug, reflecting what's circulating locally.

Overall, though, the provincial vaccine schedules are based on "decades and decades of data" says Michael Julius, Vice-President of research at the Sunnybrook Research Institute and a professor in the departments of immunology and medical biophysics at the University of Toronto.

For a better understanding of the rationale behind the vaccine schedules, it's worthwhile taking a deeper dive into the mechanics of the immune system.

At birth, an infant's immune system is still in an under-developed or immature state. That means the child can't immediately mount a strong defense against foreign microbes all on its own. However, the child does get some ongoing assistance from mom.

While still in the womb, some of the mother's immune molecules, called antibodies, are transferred to the child's bloodstream, explains Dr. Nicole Le Saux, an infectious-disease physician at the Children's Hospital of Eastern Ontario in Ottawa.

Antibodies help identify potentially harmful substances and tag them for destruction by other immune cells.

Furthermore, by breast-feeding her infant, the mother provides the baby with additional antibodies, plus immune-stimulating nutrients that are in her milk, says Prof. Julius.

The mom's antibodies are meant to serve only as temporary protection. If the child is going to survive and thrive in the world, its immune system must become self-reliant.

The maternal antibodies "are provided as long as the infant is breastfeeding, and remain in the infant only transiently," says Prof. Julius. The loss of this "passive protection" happens at roughly the same time that the child's immune system becomes better able to produce its own antibodies.

Through exposure to viruses, bacteria, fungi and other substances, the child's immune system creates a vast supply of specifically-targeted antibodies, some of which provide permanent immunity to certain illnesses. Antibodies work by recognizing antigens, or proteins, on the surfaces of the invaders. The antibodies latch onto these proteins and signal other immune cells to mount a massive counter attack.

However, during the first few months and years of life, the immune system responds at a somewhat sluggish pace. As a result, children can become extremely sick, may develop complications and even die when they encounter an especially nasty bug for the first time.

Vaccines, on the other hand, provide an opportunity for a child to develop immunity without having to go through a full-fledged infection. The vaccines contain bits of a disease-causing organism or a weakened form of it. This allows the immune system to respond and build up a supply of antibodies in advance of a real attack.

(Some vaccines also include other compounds that act as preservatives or help stimulate the immune system. Repeated studies have shown the compounds are safe and, despite the discredited claims of anti-vaxxers, don't cause autism.)

Yet even with a vaccination, an infant's immature immune system may not produce a sufficient level of antibodies. "That's why a vaccine may not be completely effective after just the first dose," says Dr. Le Saux. Furthermore, "children's immune systems probably don't create long-lasting antibodies" in the first few months of life, she adds.

For these reasons, a child will get booster shots of certain vaccines.

Under Ontario's publicly-funded immunization schedule, for instance, a child at two months of age will get a five-in-one shot for diphtheria, pertussis, tetanus, polio and haemophilus influenzae type b (Hib). At the same appointment, the child will get separate shots for Pneumococcal conjugate-13 and Rotavirus.

All of these shots are repeated when the child is four months of age. And at six months, the five-in-one shot is given once more.

This may seem like a lot of vaccinations over a relatively short period of time, but the child's immune system is quite capable of handling them, says Dr. Offit. In fact, children are literally surrounded by a multitude of microbes as soon as they descend down their mother's vaginal canal from the womb.

"Very quickly you have living on the surface of your body literally trillions of bacteria," says Dr. Offit. By contrast, the number of immune-stimulating particles in a vaccine "is literally a drop in the ocean compared to what you encounter and manage every day."

In recent years, he notes that technological advances have made it possible to produce vaccines that contain even fewer particles than they did a generation ago. The shot for pertussis, commonly known as whooping cough, "used to be a whole-cell vaccine that would have 3,000 immunological compounds and now it's three to five."

So, the biggest challenge to a child's immature immune system is not posed by the vast quantity of foreign organisms in the natural environment or frequent vaccinations in a doctor's office. Instead, the real problems come from first encounters with potentially lethal diseases when the immune system has not yet developed its own defenses.

Nonetheless, Dr. Offit says he understands why the number of childhood vaccinations might concern some parents. "They can see the shots - but they can't see the bacteria or the viruses."

Indeed, vaccines have become victims of their own success. They have been so effective at eliminating many common childhood infections that most people have no memory of the pain, suffering and deaths these illnesses once caused.

Before a vaccine for measles became widely available in 1963, epidemics of the highly-contagious illness would sweep through Canada every few years, infecting as many as 300,000 children. One in five kids who contracted the virus would be admitted to hospital with complications such as high fever, pneumonia, meningitis and encephalitis. One in 1,000 kids would die.

Dr. Offit says it would be a big mistake to stray from the official vaccine schedule as Dr. Sears has proposed in his book. "You want to make sure the child is immune before being exposed."

He adds that spreading the shots over more appointments will not lessen children's pain and anxiety. Studies show that kids experience roughly the same level of the stress hormone, cortisol, during their needle appointments, regardless of whether they get one or multiple jabs. "Basically, you are maximally stressed-out with one shot," he explains, and an extra needle doesn't make the experience appreciably worse. But bringing the child back again and again to get one shot at a time may actually increase needle phobia, he warns.

Dr. Le Saux points out that there are ways to make vaccinations less traumatic for young children. Giving a child a sip of sugar water shortly before the needle poke seems to ease the pain. As well, "breastfeeding, shortly before, during and or after the immunization" also helps.

If your daughter seems unusually upset during vaccinations, talk to your pediatrician or doctor about the various approaches for lessening the sting of the needle.

In a sense, parents who delay or forgo their own kids' shots are taking a gamble that other parents will do the right thing and proceed with all the regular vaccinations.

When the vast majority of parents vaccinate their children, the unvaccinated kids are partly protected because harmful microbes are not circulating widely in the community. It's a form of indirect protection known as "herd" immunity.

But the recent outbreaks of measles, first in United States and then in Canada, show that group protection quickly breaks down when a sizable number of parents opt out of the vaccination system.

In our age of global travel, it's also possible for an infectious bug to be introduced into your community by someone who has recently been to a place where childhood diseases are still endemic.

Consider polio, which still cripples people in some politically-unstable regions of the world -- such as Pakistan, Afghanistan, parts of Africa and the Middle East -- where there have been problems carrying out vaccination programs. The polio vaccine is one of the shots that Dr. Sears suggests that Americans -- and presumably Canadians -- no longer need.

So don't take a risk with your child's health, and stick with the regular vaccine schedule.

In the meantime, if you would like to read a far more reliable book than the one by Dr. Sears, check out a new release from the Canadian Paediatric Society (CPS). It's called Your Child's Best Shot: A parent's guide to vaccination, 4th edition.

The book is edited by Dr. Dorothy L. Moore, an infectious-disease specialist at the Montreal Children's Hospital, and it has a forward by The Globe and Mail's Health Policy Reporter André Picard.

It's available through the CPS's website.

Co-authored by Paul Taylor, Personal Health Navigator at Sunnybrook.