Immunisation, or vaccination, is a safe and effective way to protect you and your family from many dangerous diseases caused by viruses and bacteria. Examples of diseases that immunisation can protect you against include influenza, COVID-19, pneumonia, cervical cancer, hepatitis B, rotavirus, polio, tetanus, diphtheria, measles, mumps, rubella, meningitis, tuberculosis (TB), whooping cough, yellow fever, chicken pox, shingles, typhoid fever, Ebola virus, and Japanese encephalitis. There are vaccines being studied for several other diseases, such as malaria and even HIV, but they are not yet available. Most vaccines are given by injection, or a “shot,” but a few are given orally (by mouth) or in a nasal spray. They trigger a response from the immune system to certain pathogens (tiny disease-causing organisms, i.e.-viruses or bacteria). Vaccines help the body create antibodies, which are proteins the body uses to fight foreign invaders like germs and allergens. The immune system has a “memory” against pathogens it has encountered before, so when exposed to the virus or bacterium that causes the disease you have been immunised against, the body recognizes it and uses antibodies to fight the infection. This is called “immunity.” There are several different types of vaccines available.
Live-Attenuated Vaccines, aka “live vaccines,” contain live viruses or bacteria that have been weakened (or “attenuated”). These vaccines create a strong, long-lasting immune response in the body, and usually life-long immunity after 1 or 2 doses. Because they contain live viruses or bacteria, they must be kept cool to remain active, which can make these difficult to use in areas with poor access to refrigerators. Examples of live-attenuated vaccines include MMR (measles, mumps, rubella) vaccine, oral polio vaccine, rotavirus vaccine, yellow fever vaccine, varicella vaccine (chicken pox/shingles), and BCG vaccine (TB).
Inactivated Vaccines contain a version of the virus or bacterium that causes a disease that has been killed. The body still recognizes the pathogen, enough to create an immune system response. However, the immunity from inactivated vaccines is usually not as strong and long-lasting and can fade over time. More doses (“boosters”) may be needed later for continuing protection against disease. Examples of inactivated vaccines include the flu shot, polio shot, rabies vaccine, and hepatitis A vaccine.
Subunit Vaccines use a part of the pathogen rather instead of a weakened or killed version of the entire virus or bacterium to create an immune response against disease. These include polysaccharide (a sugar coating on some bacteria), protein-based, and conjugate (sugar attached to a protein) vaccines. Examples of subunit vaccines are acellular pertussis vaccine, Haemophilus influenzae type B (Hib) vaccine, human papillomavirus (HPV) vaccine, pneumococcal vaccine, meningococcal vaccine, shingles vaccine, and hepatitis B vaccine.
Toxoid Vaccines contain harmful substances created by bacteria called toxins, that cause disease. The immune response is to the toxin produced by the bacterium rather than the pathogen itself. These vaccines often also need boosters for continued protection. Examples of toxoid vaccines are tetanus and diphtheria vaccines.
Viral Vector Vaccines contain a harmless virus that has a genetic code on it that tells the immune system to create antibodies to the virus the immunisation is for. Examples of viral vector vaccines include Ebola vaccine and COVID-19 vaccine.
mRNA Vaccines contain genetic material (RNA) that tells the body to produce antibodies against a certain protein in a pathogen. mRNA vaccines are a promising new technology that could help us produce many new vaccines against dangerous diseases. Some COVID-19 vaccines use mRNA technology.
Vaccines are considered safe, but there are some expected side effects. These include fatigue/tiredness, headache, body aches, fever, and reactions such as soreness, redness, and warmth at the injection site. These reactions can be a good sign, as they are often a sign that the body is building an immune response against the disease you are being immunized against. There are a few rare, serious side effects associated with immunizations.
Allergic Reactions to a vaccine or vaccine ingredient may occur. If you or your child experience a combination of rash, hives, nausea/vomiting, swelling, a feeling of thickness in the tongue or throat, and/or shortness of breath, you should seek medical help right away.
Neurological (Nervous system) Effects resulting from vaccination are very rare but can be very serious. They include encephalopathy, seizures, or Guillain-Barre Syndrome. If you or your child experience seizures, weakness or numbness in the arms and legs, confusion, and/or severe headaches, you should seek medical attention immediately.
It is important to note that reports of vaccines causing Autism Spectrum Disorder (ASD) in children have been scientifically proven to be incorrect. There has been NO link established between vaccines and children developing autism spectrum disorder (ASD).
Many immunization shots contain vaccines for a combination of diseases, which can help decrease the number of shots received. This is particularly useful in childhood immunisations, where multiple vaccines may be given at one time. There are recommended immunization schedules for children and adults, outlining which vaccine (and boosters if needed) should be given at particular ages. In South Africa, most childhood vaccines are available for free from the government.
There are some vaccines that are not appropriate to be given in certain health conditions. For example, live vaccines are not recommended in pregnant women or people who are immunocompromised due to HIV infection/AIDS. A weakened live virus has the potential to cause disease in someone with a suppressed immune system, whereas it does not in someone with a normally functioning immune system. There are also some vaccinations that may be recommended in people with certain immune system conditions that may not necessarily be recommended for the general population. You should talk to your healthcare provider about which immunisations you and your child should receive, and when.
Immunisations are important for protecting both yourself and others from many potentially deadly diseases. Some people who cannot receive certain vaccines can be protected from infection when the people around them have immunity due to vaccines. In fact, some diseases have been eradicated (completely eliminated) due to the use of vaccines, and vaccines have helped control many disease outbreaks and have saved millions of lives worldwide. It is important to remember that vaccines are not a substitute for good hygiene and infection control measures. Frequent and correct handwashing, masking during periods of high respiratory disease (ex. Flu or COVID-19) activity and avoiding people who are sick are still important steps to take to prevent infections. Some vaccines (ex.- flu or COVID-19 vaccines) do not provide complete protection from disease but can help decrease transmission and prevent severe disease and deaths.