Pages Menu

Column originally published Sep 9, 1998
Column last revised/updated on Jan 12, 2019

There Is A New Acellular Whooping Cough Vaccine

Question: When our older son was two months old, he had severe reaction to his first vaccine with screaming and high fever. Our doctor felt that it was because of the whooping cough vaccine, and told us not give him any more of this vaccine. He did not react to other vaccines since, and he is three now. I am pregnant again with our second child. I am terrified of our experience. Is there any way we can avoid such a reaction in our future child?


Thank you for asking this important question. You should be glad to hear that there is a new whooping cough vaccine available. Let me try to give you more details so that you can make some informed decisions.

The original whooping cough (also called pertussis) vaccines were made by growing these bacteria in the laboratory and then killing them with chemicals. These bacteria contained certain poisons inside their cells, called “endotoxins,” which are responsible for most of the side effects of the vaccines. These original vaccines are now called “whole cell” vaccines because they contain complete bacteria, although these bacteria were already killed.

The common side effects associated with these whole cell vaccines are local discomfort, pain and swelling, fever (sometimes over 40oC), irritability, and febrile convulsions. Uncommon complications include prolonged crying for more than 3 hours, and “shocklike state” where the child becomes very pale and unresponsive.

Even more rare are severe allergic reactions that happen within minutes after receiving the vaccine, and severe brain disorders and permanent brain damage. Research has shown that the great majority of these brain conditions are not because of whooping cough vaccine.

Over the last few decades, scientists have worked very hard to develop new vaccines that are just as effective, but without most of these side effects. They have discovered that whooping cough bacteria contained several proteins which can induce immunity in our body. By carefully extracting these proteins, they were able to produce new vaccines which did not contain dead bacteria. As a result, they are called “acellular vaccines.” Acellular means without cells.

These acellular vaccines have been tested extensively around the world, and were found to be as effective as the “whole cell” vaccines. The first acellular vaccine was licensed in Canada last year. Since then, all the provinces have incorporated the “acellular” vaccine to replace the “whole cell” vaccine in their vaccination regimens.

Compared with “whole cell” vaccines, the new “acellular” vaccines cause much fewer side effects. Children have less localized swelling or pain, and fever tends to be lower. As a result, the chance of getting febrile convulsions is also much reduced. The more serious prolonged crying and “shocklike state” are also much less frequent in the new vaccines. It is too early to tell whether the new vaccines will be less likely to cause severe allergic reactions. We also don’t know whether severe brain disorders will ever happen with the new vaccine.

Your next child certainly should be vaccinated with the new “acellular” vaccine, just like any other child born in Canada. It may still be advisable to give him/her acetaminophen after the vaccine if he develops fever. Children are recommended to receive this vaccine at 2, 4 and 6 months, with booster doses at 15 to 18 months, and finally at 4-6 years of age before entering school.

In addition, you may want to discuss with your physician whether your son should receive further doses of this new “acellular” vaccine. High fever over 40.5oC and prolonged crying for over 3 hours constitute “precautions” for future doses of vaccine. This means that future doses should be given with caution. These side effects are not contraindications for whooping cough vaccine.

The new vaccines are safer and less likely to cause these side effects. Of course, one has to balance the benefits and risks of additional vaccination. Outbreaks of whooping cough occur regularly in many communities across Canada. Children who did not receive the full 5 doses of whooping cough vaccine are more likely to contract the disease. When they get infected, these children also become sicker than those fully vaccinated children.

[Note to Readers:  After using this new acellular vaccine for twenty years, it is clear that it is not nearly as effective in preventing pertussis, or whooping cough. Furthermore, immunity against the infection decreases much faster over time compared with the whole cell vaccine. Many adults who received acellular vaccine as children have lost their protection. Therefore, adults are advised to receive booster doses of this vaccine. Women are advised to receive this vaccine during pregnancy to protect their babies from contracting whooping cough during the first few months of age, when the first doses of vaccine will take time to develop and provide immunity.]