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Column originally published Apr 30, 2002

New Pneumococcal Conjugated Vaccine Is Available

Question: Our son is 15 months old. Since starting daycare at 9 months of age, he has been getting one ear infection after another. Sometimes it takes two to three courses of antibiotics before he would improve, and then within a couple of weeks, he would be sick again. We are concerned about the amount of antibiotics that he has taken already. Is there an end to this cycle of infection? I read in the newspaper about a new vaccine that can prevent ear infections. Should we get him this vaccine?


The vaccine that you read about is the Pneumococcal Conjugate Vaccine (PCV7). This vaccine may be able to prevent some of the ear infections in your son. Let me explain to you and other parents about Pneumococcus and this new vaccine in greater detail.

Pneumococcus is also called Streptococcus pneumoniae. It is responsible for 20% of ear infections, sinus infections, and pneumonia in young children. More importantly, these bacteria can cause more serious medical conditions like infection of the blood (also called bacteraemia) and meningitis.

Data collected around Canada in the past ten years reveals a more comprehensive picture about the danger of Pneumococcus. Children under 5 years of age are most susceptible to serious pneumococcal infections. Every year, 65 children will contract pneumococcal meningitis. Another 700 children will develop bacteraemia, 2200 children will be hospitalized for pneumonia, and a further 9000 children will have pneumonia that do not require hospitalization. Altogether, 15 children under 5 years of age would die every year because of serious pneumococcal infection.

As you can see, the problem of Pneumococcus goes far beyond ear infections. Nevertheless, ear infections impact on children and parents greatly. It was estimated that every year, children in Canada altogether have about 1 million episodes of ear infections, and visit their doctors 1.8 million times. Again most of these infections affect children under 5 years of age, and the great majority require one or more courses of antibiotic for treatment.

If it is possible to invent a vaccine that can prevent pneumococcal infection, the benefit to children would be enormous. Unfortunately there are many hurdles that scientists have to overcome. The greatest one being the shear number of strains of Pneumococcus: there are altogether 90 different strains. It is almost impossible to produce one vaccine that can prevent all of them.

For many years, a pneumococcal polysaccharide vaccine (PPV23) was available. It contains the outer coating of 23 different strains of Pneumococcus that cause the great majority of serious infections in North America. It is quite effective in older children and adults. Everyone over 65 years of age should receive this vaccine.

Unfortunately, PPV23 is not effective in children under 2 years of age. The polysaccharides cannot induce immunity in very young children with an immature immune system. Luckily, by tagging the polysaccharide with a protein, even children as young as 2 months of age can respond to the vaccine and produce effective antibodies.

By analysing the strains that cause serious pneumococcal infection in children under 5 years of age, scientists concluded that 7 different strains (14, 6B, 19F, 18C, 4, 23F, and 9V) are responsible for greater than 80% of these infections. This is a manageable number. The polysaccharide of each strain is tagged with a protein, and the vaccine is produced by mixing all seven vaccines together. This new vaccine is called pneumococcal conjugate vaccine (PCV7).

Extensive research has shown that this new PCV7 vaccine is extremely effective in preventing serious pneumococcal infections like pneumonia, bacteraemia, and meningitis. Its effectiveness in preventing ear infections and sinus infections still awaits additional studies.

There is another compelling reason to use PCV7 to prevent pneumococcal infections. Pneumococci resistant to multiple antibiotics are found in increasing numbers all across North America as well as the rest of the world. Doctors are forced to use more and more powerful antibiotics to treat patients with serious pneumococcal infections. It would make great sense to prevent these infections and reduce use of antibiotics.

The National Advisory Committee on Immunization (NACI) recommends all children receive PCV7 at 2, 4, and 6 months of age as part of their primary series of vaccination, followed by a booster dose at 12-15 months of age. For those children between 7 to 11 months that are not immunized, they should be given 2 doses of vaccine at 8 weeks apart, followed by a booster dose. Your son, at 15 months of age, should be given 2 doses at 8 weeks apart.

This vaccine does not contain mercury, and causes very little side effects. Presently, it has to be given in a separate injection. Additional research is underway to determine whether it can be mixed with other vaccines to reduce the number of injections given to young children.

As a paediatrician, I would like to see this vaccine being provided universally to all children under 5 years of age, when they are most susceptible to pneumococcal infections. Around 10 years ago, another meningitis vaccine (called Hib—Haemophilus influenzae type b) was adopted by all provinces and territories. Within a few years, we have virtually eliminated all meningitis as well as other serious infections caused by Hib. It is possible that this same scenario may also happen with PCV7.

Until then, you may want to discuss with your doctor about the benefits of PCV7. You should also explore other causes of ear infections. Children in daycare are more likely to develop ear infections because they are exposed to more viruses. Allergy can also predispose children to recurrent ear infections.

[Note to Readers: Newer Pneumococcal Conjugated Vaccine have become available since this column was written, with more strains of Pneumococci covered. Also, all provinces are covering the cost of this essential vaccine for all children. Cheers!!]