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Column originally published Nov 9, 2004

New Acellular Whooping Cough Vaccine In Teenagers Can Prevent Infection In Children

Question: Our teenage daughter is in junior high school. Last week, she brought home a notice about a whooping cough vaccine study. I remember she had received all her childhood immunizations. I am worried about this vaccine study. I don’t want my daughter to be used as a guinea pig. Please give me advice what I should do.


The whooping cough vaccine that is offered to school-aged children is actually a fully-licensed vaccine designed for adolescents and adults. I understand some additional research is being carried out at the present time to further understand how we should use this vaccine to prevent the spread of whooping cough in children and adults.

Whooping cough, also called pertussis, is one of the preventable diseases that is still causing major outbreaks across North America. It is caused by a germ called Bordetella pertussis. Every few years, epidemics of whooping cough would spread through large and small communities, both in Canada as well as in United States.

Whooping cough is most serious in very young children. They develop cold-like symptoms at the beginning, followed quickly by severe bouts of cough. Although the cough can be fairly characteristic, many professionals who don’t see this problem frequently can miss the diagnosis.

When the cough is severe, these children can develop bouts of vomiting during the coughing spells. In general, the cough is most severe in very young children. Some can lose weight or get dehydrated as a result of decreased feeding and recurrent vomiting.

Before the development of whooping cough vaccine, many young children died every year from lack of oxygen due to severe cough spasms. Since 1940s, deaths from whooping cough have steadily declined. The original vaccine consisted of killed bacteria, and is known as the ‘whole cell vaccine.’ It was effective in preventing serious illness, but it also caused a number of side effects.

Between 1980 and 1996, vaccine manufacturers modified the way that they produce the vaccine in order to reduce side effects. Unfortunately, the end result was a less effective vaccine compared with the previous one. Children who received their routine immunization during those years were not as well protected, and the immunity didn’t last very long.

Since 1997, a new whooping cough vaccine was licensed in Canada. It is called ‘acellular’ vaccine. The word acellular means that it doesn’t contain whole bacterial cells. Instead, the whooping cough bacteria were broken up during manufacturing process. Only parts of the bacteria that are important in producing immunity are purified and concentrated into the vaccine. As a result, the new vaccine is more effective and less likely to produce serious side effects.

This new acellular vaccine has been used in all provinces since 1997 for immunization of young children at 2, 4, and 6 months of age. Booster shots are given at 18 months and 4-6 years. This acellular vaccine is combined with diphtheria, tetanus and polio vaccines so that many parents are not even aware of the significant change in their children’s immunization.

With the old ‘whole cell vaccine,’ no booster dose can be given after 4-6 years of age, because the vaccine can cause serious side effects in older children and adults. Although we knew that immunity to whooping cough declined with time, there was no safe vaccine that could be used, until now.

The new acellular vaccine has been tested extensively in adolescents and adults. It is very effective in producing immunity against whooping cough. However, we still don’t know how long this immunity will last. The side effects are minimal, and they include mild fever, local swelling, and pain. The new vaccine, in combination with diphtheria and tetanus, and has been licensed in Canada for use in adolescents and adults.

You may wonder: Why should there be a whooping cough vaccine for adolescents and adults? Traditionally, whooping cough is recognized as a childhood illness. Children can get very sick with whooping cough, but not adults. However, recent research has actually shown that almost ¼ of all documented cases of whooping cough in Canada occur in adolescents and adults. Most of them do not present with the typical cough spasms. Instead, they seem to have a prolonged cold, with a cough that doesn’t want to go away. This cough can last for many weeks, and does not respond very well to treatment.

Because it is so hard to recognize whooping cough in adolescents and adults, they become the source of infection for young children. Although they have a nagging cough, they are still able to go to school or to work, all the while spreading the bacteria to those around them, including young children.

By immunizing adolescents and adults, we increase their immunity against whooping cough, so that they won’t get infected when exposed to the bacteria. This, in turn, would reduce the circulation of whooping cough bacteria in the community, and reduce the chance of young children getting infected.

I hope you understand now why it is important to get school-aged children, including your daughter, immunized with this new acellular whooping cough vaccine.