What is immunisation

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					What is immunisation?
Vaccination, or immunisation, is considered one of the most successful public health strategies against infectious diseases. ‘Alongside the provision of clean water and proper sanitation, vaccination is the most important health measure undertaken to protect public health,’ says Avhashoni Tshatsinde, Health Programme Coordinator at the South African Vaccination and Immunisation Centre. The World Health Organization (WHO) says that well over two million lives are saved through immunisation each year. And according to the Expanded Programme on Immunisation of South Africa (EPI–SA), since the introduction of vaccines in South Africa, rates of diseases, such as measles, polio, pertussis (whooping cough), diphtheria and meningitis caused by haemophilus influenza type b (Hib) have declined by 90 percent. WHO also states that in addition to preventing illness and saving lives, vaccines are extremely cost–effective. They estimate that for every $1 spent on vaccines, it saves $7 in medical costs and $25 in overall costs. South Africa spends more than R80 million a year on vaccines and the Department of Health strongly recommends that all children be vaccinated. And although the government has not made it compulsory, many crèches and schools require immunisation records for admission. How immunisation works When altered bacteria or viruses in the form of vaccines are injected into your body, instead of causing the disease, they stimulate your immune system to produce antibodies to fight the disease. Your immune system then has the antibodies necessary to respond quickly if you come into contact with the real disease. It usually takes several doses of a vaccine to create long–lasting immunity, and some vaccines require regular booster shots throughout adulthood. Vaccine–preventable diseases Diphtheria is a throat infection that causes breathing difficulties. Up to 10 percent of diphtheria patients die, even if treated. In South Africa, less than 10 cases have been reported in the past five years, due to high vaccination coverage. Tetanus (lock jaw) is not a communicable disease, but is caused by bacteria that enters a cut or wound. It is characterised by muscle spasms, initially in the jaw, and can lead to breathing and heart problems, and death unless treatment is given. Pertussis, or whooping cough, initially resembles flu, but progresses to severe coughing fits that can make it difficult for the child to eat and breathe. It is generally mild in older children, but dangerous for infants, especially newborns. Globally, up to 40 million cases occur each year. Tuberculosis (TB) can lead to meningitis in young children. It also causes coughing, chest pain and even death if left untreated. It is estimated that 1.6 million deaths resulted from TB in 2005. Polio is a highly infectious disease caused by a virus that attacks the nerves and can cause total paralysis in a matter of hours. It mainly affects children under five. South Africa has been free from wild polio since 1989. According to the WHO, polio cases have decreased by over 99 percent since 1988 due to immunisation. There are two types of polio vaccine, a weakened live vaccine that is administered orally (OPV), and an inactivated vaccine (IPV) that is given by injection.

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Hepatitis B can be transmitted to infants, although its main risk factors include drug use and sexual activity. It increases the risk of serious liver disease, including cirrhosis and liver cancer, and it is second only to tobacco as the leading cause of cancer in humans. It is estimated that at least three million South Africans are chronic hepatitis B carriers. Serious side effects of this vaccine are rare. In about one of every 600 000 doses a child can experience hives, breathing difficulties and a drop in blood pressure, but no one has ever died from the vaccine – whereas about 5 000 deaths occur from the disease each year. Hib causes pneumonia, meningitis and other diseases, mainly in young children, particularly those between four and 18 months old. In 2000, it caused about three million cases of serious disease, and 386 000 deaths in young children. This DTP–Hib vaccine combines the vaccines for diphtheria, tetanus, pertussis and haemophilus influenza type b into a single shot. Measles causes a rash and high fever and can lead to dehydration, pneumonia, brain damage and death. In 2006, the WHO estimated that there were 242 000 measles deaths globally: translating to about 663 deaths every day or 27 deaths every hour. Almost half of these deaths occur in Africa. A recent study indicated that children not vaccinated against measles were 35 times more likely to get the disease. It has no major side effects, except that in 5 to 10 percent of cases, a measles rash can develop a week after the vaccine is administrated, but it only lasts for a day or two. Are vaccines safe? ‘People need to realise that there will always be side effects with vaccinations – just as there is with any other pharmaceutical,’ says Tshatsinde. ‘All vaccines go through various stages of research and clinical trials to ensure safety and efficacy, and need to be approved by international and national regulatory bodies. There is never a guarantee that they are completely harmless for each individual, but certainly the benefit far outweighs the risk for the majority.’ Mild side effects of many vaccines include pain, swelling and redness at the site of the injection, fatigue, mild fever, irritability, loss of appetite and headache. Other vaccinations Parents may wish to give their children additional vaccines that are available in the private sector, including:
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MMR vaccine – against measles, mumps and rubella. There has been speculation that the MMR vaccine is linked to autism, however, various studies concluded that no evidence exists of an association. Varicella vaccine – against chicken pox Meningococcal vaccine – against septicaemia and meningitis Influenza vaccine – against the flu Rotavirus vaccine – against severe diarrhoea Pneumococcal vaccine – against pneumonia and meningitis

‘Overall, vaccination has been proven to be safe and beneficial,’ says Tshatsinde. ‘There is no doubt that it has had a major impact on improving lives, particularly those of young children.’ Interesting facts
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In April 2008, the rotavirus and pneumococcal vaccines were approved for incorporation into public sector’s routine schedule. They might be rolled out within the next two years. A vaccine has been developed for the human papillomavirus. It can protect women from the virus that can lead to cervical cancer. It is recommended for girls between 12 and 26 years of age. In 1979 smallpox was the first disease to be globally eradicated due to the efforts of immunisation. Next on the list is polio, which is now only endemic in four countries in the world: Nigeria, India, Pakistan and Afghanistan.

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Routine vaccination schedule The following childhood vaccines are supplied free of charge from the government at public local clinics and community health centres. Birth: 6 Weeks: 10 weeks: 14 weeks: 9 months: 18 months: 6 years: 12 years:
BCG, OPV OPV, DTP–Hib, HBV OPV, DTP–Hib, HBV OPV, DTP–Hib, HBV measles vaccine OPV, DTP, measles vaccine OPV, Td Td

Key: BCG – bacillus Calmette–Guérin vaccine against tuberculosis; OPV – oral polio vaccine; DTP–Hib – diphtheria, tetanus, pertussis (whooping cough) and haemophilus influenza type b vaccine; HBV – hepatitis B vaccine; Td – tetanus and low–dose diphtheria vaccine Written by Tara Lerner Bankmed, Spring 2008

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