The process of vaccination to prevent illness is called immunization. Canada's immunization programs compare well with those of other countries but many infections continue to threaten our health. As new vaccines are developed, our ability to protect our health gets better. This article will describe some important developments in immunization.
Pertussis, commonly called "whooping cough," causes an illness with severe coughing. Infants and children may have trouble breathing, eating and drinking because of the coughing. The illness may last for weeks and may lead to pneumonia, convulsions and even death. The goal of the per-tussis immunization program is to vaccinate at least 95 per cent of children.
Recently, a new vaccine was licensed for use in Canada. It is not only thought to be better at preventing whooping cough than the older one, but also causes fewer side effects. This is really good news, because many people were choosing not to be immunized for fear of the side-effects of the old vaccine. The low immunization rate resulted in periodic outbreaks of pertussis. These "acellular" vaccines are not really new. They have been used in Japan for 15 years but only recently licensed in Canada for use in infants. The vaccine is given in combination with other childhood vaccines for diphtheria, tetanus, polio and Haemophilus influenzae type b (Hib) vaccine.
Redness, soreness and swelling at the injection site are much less common with acellular vaccine than with the old "whole-cell" vaccine. Fever, irritability, drowsiness, persistent crying, limpness and convulsions are also less. Fever after the acellular vaccine is so uncommon that routine use of acetaminophen (Tylenol™) after getting the shot is no longer recommended for most children.
Some older children and adults did not receive the five recommended doses of pertussis vaccine because they had reactions to it. It was thought that the negative side effects outweighed the benefit. With so few side-effects from the new vaccine, studies are underway to learn if these people should be immunized. They would not get the illness, and also not be at risk of passing it on to infants and young children in whom the illness can be very serious. The only people who should still not be vaccinated are those who had severe allergic reactions to it the first time. Anyone else who did not complete the immunization should consult a doctor or public health unit about receiving the acellular vaccine.
Hepatitis A and B are both viruses that can cause inflammation of the liver (hepatitis, "yellow jaundice"). The hepatitis A virus (HAV) is spread through contaminated food and water. Hepatitis B (HBV) is spread through infected blood or body fluids such as semen. It can be transmitted sexually, or during pregnancy from mother to baby, often during the birth process. HBV is a more serious infection than HAV because it can become a chronic infection, causing liver cirrhosis, liver cancer and even death.
A Canadian goal has been set to reduce the amount of HBV in children and young adults by 90 per cent by the year 2015. This goal can be achieved through a three-dose series of immunizations given to infants or school-aged children (Grades 3-7). Although it is recommended that most Canadian children be immunized against HBV, the age at which it is given varies across provinces and territories.
Hepatitis A immunization is recommended for:
Hepatitis A and B vaccines are effective in protect-ing against these two types of hepatitis. The length of time hepatitis A vaccine protects is not known yet, but it is expected to work for as long as 20 years. Hepatitis vaccines are among the safest of vaccines. Their side-effects and bad reactions include mild, brief tenderness, redness and swelling at the injection site. These reactions are more common in adults than in children.
The pneumococcus bacteria can cause bacteremia (a serious infection of the blood), meningitis (a life-threatening infection of the covering of the brain) and several respiratory infections, including pneumonia. A vaccine is available that pro-tects against 23 pneumococcus bacteria. Currently it is being offered to selected groups across Canada. Those who should receive the vaccine are similar to those who should get the flu vaccine. They include people:
The vaccine can be given to anyone over the age of two. Unlike the flu shot, which is given every fall, the pneumococcal vaccine is given less often (usually just once), and in many cases, protects for life. The exact recommendation depends on your reason for immunization and also varies among provinces and territories. As with other vaccines, side-effects of this one include mild soreness, redness and swelling at the injection site.
A new pneumococcal vaccine, called a conjugated vaccine, has just been licensed. It protects against 7 types of pneumococcus and can be given to children under two years of age. It is likely that this vaccine will soon become part of routine childhood vaccination programs.
Strains of bacteria that resist antibiotics are becoming more common. The problem is most serious in hospitals. The pneumococcal vaccine helps to prevent these strains developing because most people who are immunized will not need antibiotics to fight the bacteria. The bacteria do not become exposed to antibiotics, and do not get the chance to develop ways of defeating the drugs.
Neisseria meningitidis or meningococcus is the common cause of meningitis and serious blood infections in children and teenagers. Recent out-breaks of this infection across North America have required mass vaccination to control the spread of disease.
The old vaccine was not effective in young children but a new conjugated vaccine has been released which can be given to young children and infants. This is another vaccine which may be incorporated into routine vaccination schedules.
Immunization is an important part of basic health care. If you have fears or questions about any vaccines, talk to your doctor. The chances are high that you will receive the information and reassurance you need.