TORONTO — A high percentage of two-year-old kids have been vaccinated against a variety of childhood diseases, according to a Statistics Canada survey, but some immunization rates still fall below what’s considered optimal.
The 2013 Childhood National Immunization Coverage Survey released Tuesday found that 89 per cent of two-year-olds had received the recommended immunization against measles, mumps and rubella, while 77 per cent had all their shots for diphtheria, pertussis (whooping cough) and tetanus.
Uptake of the polio vaccine was 91 per cent and 73 per cent of kids had been inoculated against chickenpox, the survey of 5,500 parents and guardians found.
The survey also collected data on immunization against the human papilloma virus for girls aged 12 to 14 and 17. The HPV vaccination rate was 72 per cent for 12- to 14-year-olds and 64 per cent for 17-year-olds. HPV is a sexually transmitted infection that causes most cervical cancers, as well as some other genital cancers in both women and men.
The survey also found that a small proportion of Canadian children — 1.5 per cent — had never received immunizations of any kind.
“These are really sub-optimal,” Dr. Joan Robinson, an infectious disease specialist at Stollery Children’s Hospital in Edmonton, said of the overall vaccination rates.
“What we would like to see is about 90 per cent uptake for all of the vaccines.... That’s the rate that you usually need to get decent herd immunity.”
Herd immunity occurs when enough individuals in a given population have immunity through vaccination or previous exposure, which confers protection to those who aren’t immunized by preventing a contagious bacteria or virus from setting up a chain of infection.
“But for measles, because it’s so contagious, we think that even 95 per cent immunization might be what (we) would need to prevent spread if a case is introduced into a community,” said Robinson.
“Very few” children, she said, can’t be vaccinated — typically because of a suppressed immune system from being on chemotherapy or drugs that prevent organ rejection, for instance. Having a 90 per cent coverage rate usually means such children benefit from herd immunity.
“But almost all of the children can be immunized and should be immunized.”
The survey also looked at parents’ and guardians’ attitudes towards inoculation.
Most agreed that childhood vaccines are important for children’s health (97 per cent); that childhood vaccines are effective (97 per cent); and that vaccines are safe (95 per cent).
But at the same time, about 70 per cent of respondents were concerned about potential side-effects from the shots.
More worrisome for public health officials was that 37 per cent worried their child could catch the disease the vaccine is meant to protect against, while 17 per cent believed homeopathic and other alternative medicine practices could eliminate the need for vaccines — both notions that experts say are untrue.