Vaccine Safety

Frequently Asked Questions

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What would happen if we stopped immunizing?

Answer: Experience from other countries shows that diseases quickly return when fewer people are immunized:

• Ireland saw measles soar to more than 1,200 cases in the year 2000, as compared with just 148 the previous year, because immunization rates fell to around 76%. Several children died in this outbreak.
• A large outbreak of rubella (German measles) occurred in Nebraska in 1999. All 83 cases in this outbreak involved adults who had not been immunized. Most of them came from countries where rubella immunization is not routine. The outbreak spread from a meat-packing plant to the general community, including several pregnant women and two day care centres. The greatest danger from rubella is to infants, who may be born with congenital rubella syndrome if their mothers are infected during pregnancy.
• In 1994, there were 5,000 deaths due to diphtheria in Russia after the organized immunization system was suspended. Previously, Russia (like Canada) had had only a few cases of diphtheria each year and no deaths. Diphtheria toxoid came into routine use in the 1930s, but even today diphtheria remains a severe disease. About one person in 10 with diphtheria still dies in spite of medical treatment.
• In the U.K., a major drop in rates of immunization against pertussis (whooping cough) in 1974 was followed by an epidemic of more than 100,000 cases and 36 deaths by 1978.
• Japan had 13,000 cases and 41 deaths from whooping cough in 1979, after only 30% of children received pertussis immunization. In earlier years, when most children received vaccine, Japan had only a few hundred cases of whooping cough and no deaths.
• Sweden had a similar experience with pertussis. When vaccination programs restarted, the number of cases fell once again.

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