- Researchers from the University of
Toronto carried out a study to understand the effectiveness of acellular
- The vaccine lowered incidence of
pertussis in Canada
- The immunity provided by the
vaccine lasts only for a period of 3 years with loss of immunity after 7
The vaccine that
is currently available for pertussis is highly effective for a period of three
years, after which its effect dwindles, says a study by researchers from
The University of Toronto.
Dr. Natasha Crowcroft from The
University of Toronto adds "Despite waning immunity of the whooping cough
vaccine, it's important to note that the number of cases of pertussis in Canada
is still quite low. The most effective way parents can prevent whooping cough
is to have their children immunized on time."
‘Vaccination at the right time could prevent infection.’
The Pertussis Vaccine
The pertussis vaccine is an acellular vaccine
as it does not contain the full organism, and is used to protect against a
bacterial infection that is spread by coughing or sneezing.
The current vaccine has been
used in Canada since 1997 and also used in other countries like Australia, New
Zealand, Europe and North America. It is administered to children, teenagers,
infants and adults to prevent the incidence of pertussis.
Symptoms of Pertussis
Pertussis is also called the
because of the characteristic
whoop that is heard when the patient coughs. The initial symptoms include
- Mild fever
- Low grade runny nose
- Occasional cough
condition advances it can lead to
Vaccination Chart for Infants
- Nausea and vomiting
- Characteristic whoop during
be protected against whooping cough to avoid the severe infection that it can
lead to. The following is the time of vaccination for infants
- At 60 days after birth
- At 120 days after birth
- At 180 days after birth
- Between 1 year 3 months to 1 and a
- Between 4 to 6 years
current research by Dr. Crawford shows that the effectiveness of the vaccine
could wane over time, she is quick to add that she doesn't want anyone to avoid
taking the vaccine altogether.
Decrease in Disease
Incidence after Pertussis Vaccine
- The incidence of pertussis prior
to Canada's vaccination program was 156 cases per 100 000 people.
- After the vaccination program had
started, the incidence lowered to 2 per 100 000 in 2011 to 13.9 in 2012.
This shows that
the pertussis vaccine program conducted in Canada was highly effective in
lowering the incidence of
Study on Effectiveness
of Pertussis Vaccine
studied 5867 people between the years between 1992 to 2013. Out of which
- 486 tested positive for the presence
- 5381 were negative for pertussis
- Up to 3 years after vaccination,
there was immunity against the infection.
- 7 years after vaccination, there
was little immunity.
- The risk of getting pertussis
increased by 27% every year.
effectiveness of the newer acellular pertussis vaccine was compared with the
whole organism vaccine used in certain countries, it was found that those
individuals who received the newer vaccine during the first three infant
vaccinations were twice as likely to get pertussis when compared with
individuals who received the whole organism vaccine.
of the study conclude by saying "... our finding that the low-effectiveness
whole-cell vaccine is still better for priming than the currently used
acellular vaccine nearly 2 decades after the change in practice has profound
implications for understanding the effectiveness of the pertussis vaccine."
from using the whole organism vaccine to the acellular vaccine due to poor
effectiveness of the whole organism vaccine that was used earlier. However,
newer whole organism vaccines that are available in the market are found to be
The results of
this study are supported by other studies conducted in The United States and in
The U.K that have shown a decreased immunity
over a period of time.
The lack of
immunity after a period of 7 years is an alarming fact in the fight against
pertussis. The optimum level of immunity can be maintained by
- Vaccinating pregnant women.
- Re-immunizing children after 7
- Re-immunizing when going to
pertussis prone areas.
provides an insight into the corrective measures that need to be incorporated
in vaccinating against pertussis in Canada. These measures will serve to
provide the right defence against the disease and prevent its spread.
- Pertussis (Whooping Cough) Vaccine - (http://www.vaccines.gov/diseases/pertussis/)
- Pertussis (Whooping Cough) - Signs and Symptoms - (http://www.cdc.gov/pertussis/about/signs-symptoms.html)