WHEN HARMFUL germs invade the body, they attack, multiply and cause infections and illnesses. Your immune system – white cells and antibodies – is your body’s natural defence against harmful germs. If your body is infected with harmful germs for the first time, it usually takes several days for it to fight the germs and overcome the infection.
After you recover from the infection, your body develops immunity to the disease. This means your immune system is now primed and remembers how to fight off the germ, and will produce a stronger, quicker response that will protect you from infection and illness the next time you are exposed to it.
Vaccines are tools for prevention of infection illnesses, not treatment. It is important for children to get vaccinated when they are healthy, before they are exposed to harmful germs, especially during infancy and early childhood when there immune system is underdeveloped and when they are vulnerable to harmful infections.
According to Dr Julia Rowe-Porter, acting director at the Family Health Unit, Health Services Planning and Integration Branch at the Ministry of Health and Wellness (MOHW), vaccines are harmless substances, usually given by injection, that help your body to develop immunity to harmful germs before you get exposed to them.
“They do this by mimicking harmful invading germs without causing illness, and stimulating the production of antibodies and germ-fighting tools so that your body will be ready to fight off infections the first time you are exposed,” Dr Rowe-Porter said.
Vaccines, she said, make your immune system react stronger, quicker and longer when harmful germs invade your body. This is particularly important for protection against infection that are associated with severe illness, hospitalisation or death.
Most childhood vaccines she said are made of harmless inactivated or dead particles called antigens that cannot cause the disease they are supposed to prevent, like tetanus (lock jaw), Pertussis (whooping cough), diphtheria, Hepatitis B, inactivated poliovirus (IPV), influenza (the flu) and human papillomavirus (HPV) vaccines.
“Some vaccines like oral poliovirus (OPV), measles, mumps, rubella (MMR) and BCG (to protect against tuberculosis) are made of live weakened forms of germs and may, in rare cases, cause this disease in persons whose immune system is very weak when they are vaccinated. Such persons are not eligible for receiving live vaccines,” Dr Rowe-Porter said.
Vaccine-preventable diseases can spread very rapidly through the school community and have devastating effects on our population if most, if not all children, are not adequately immunised.
“At least 95 per cent of children or 19 out of 20, must be adequately vaccinated to prevent or interrupt the rapid spread of VPDs (vaccine-preventable diseases) if there are cases present in the population. The remaining five per cent of children accounts for those that are not eligible to get vaccinated for medical reasons, for example, immunocompromised, known severe vaccine reactions,” Dr Rowe-Porter said.
According to her, Jamaica’s Immunization Regulations of 1986 (amended 2013) also requires that all children under age seven years of age must be adequately vaccinated before registration for school, including daycares, nurseries and basic schools.
“Vaccines contain controlled amounts of antigens in safe, effective doses. Infants and young children are often exposed to several germs at a time in their natural environment, so exposure to multiple antigens at one time is not unusual for the immune system. Importantly, it is better for babies to receive multiple vaccines at the same time than to space the injections out because the latter prolongs the time it takes for adequate vaccination, increases the risk of infection before the baby is adequately protected, and increases the number of visits for vaccine appointments,” Dr Rowe-Porter said.
“Also, with technological advances over the years, many vaccines are given in combination doses. For example, the 5-in-i Pentavalent and 3-in-1 MMR vaccines to reduce the number of injections,” she added.
Harmful reactions, she said, can include severe allergic reactions. Confirmed vaccine-related allergic reactions are very rare in children, ranging between 0.65-1.45 cases per million vaccine doses. Most vaccine-related reactions are self-limited reactions like fever and redness, swelling and pain at the injection site which resolve in a few days.
Diseases like polio, rubella, measles and diphtheria and newborn tetanus that Jamaica eliminated decades ago, she said are still circulating in other countries. With countries easily connected by global travel and trade, there is a real risk of reintroducing these diseases in Jamaica. Maintaining high levels of vaccination coverage in our population is essential to preventing this from occurring.
“Most childhood vaccinations confer lifelong immunity if doses are given according to the national immunisation schedule. Some vaccines like the influenza vaccine are given annually, just before the flu season begins, based on the circulating strain of influenza virus,” Dr Rowe-Porter said.
All vaccines, she said, undergo a rigorous process of development, testing and regulation before being licensed and approved for use in humans. This includes several phases of pre-clinical and clinical trials to determine their safety and efficacy and effectiveness. There is also a system for tracking and reporting that is designed to protect the population if concerns about vaccines safety arise and to improve vaccine effectiveness.
“All healthcare workers, school operators and parents must ensure that children’s vaccinations are up to date and recorded in their Child Health and Development Passport or immunisation cards. Take the passport or card to your child’s or ward’s doctor or nearest health centre to check if he or she is adequately vaccinated,” Dr Rowe-Porter said.
The MOHW sets, monitors and coordinates the policies and programmes that govern the national Expanded Programme on Immunization that was established in September 1977. The Regional Health Authorities and Parish Health Departments operate the immunisation services through the public health facilities across the island.
Vaccines provided by the Government of Jamaica are offered free of cost at public health centres. There are over 300 public vaccination sites across the island. Visit www.moh.gov.jm [3] or the MOHW’s social media pages (@themohwgovjm) for more information.