Chickenpox, also known as varicella, is a common, very contagious childhood illness. It is caused…
What are childhood immunisations?
Childhood immunisations are a series of vaccines that are given to infants and young children.
Immunisation creates a way for the body's immune system to form an immune memory to infectious organisms. Immune memory delivers a more quick, specific and efficient defence to infections by a specific organism, protecting the child from future disease.
Immunisation programs and schedules
Worldwide, governments run programs to immunise their citizens against disease. Immunisation programs and schedules can vary between countries (and sometimes between states within one country), according to:
- The specific health challenges in the region;
- The presence of specific at-risk populations in the region;
- Available funds, and;
- Political and cultural considerations.
That said, immunisation schedules around the world normally follow a fairly standard path. Vaccines commonly included in childhood immunisation programs are:
- Hepatitis B;
- Poliomyelitis (polio);
- DTaP - diphtheria, tetanus, acellular pertussis (whooping cough);
- Haemophilus influenza B (Hib);
- MMR - measles, mumps, rubella;
- Chickenpox (varicella);
- Human papillomavirus (HPV);
- Meningococcal, and;
- Pneumococcal (PPV).
Often, vaccines will be combined, such as the 3-in-1 or the 5-in-1 vaccine. This is done to simplify vaccination and reduce the number of injections needed. Combining vaccines does not increase the risk of adverse effects (see the 'Safety and parental concerns' section below).
Children living in or travelling to areas where certain diseases are common may receive additional vaccinations. These can include:
- Bacillus Calmette-Guérin (BCG) vaccine against tuberculosis;
- Hepatitis A;
- Yellow fever;
- Typhoid fever (for children over two years of age), and;
Benefits of immunisation
Protection from disease
With vaccination, the child can attain immunity without being exposed to the actual disease and without risking its complications.
Humans have been using vaccinations for hundreds of years. As a result, many childhood diseases that had once plagued humanity, causing illness and death, are now rare events.
When immunisation rates drop below a threshold level, outbreaks of disease are likely. These outbreaks will not affect immunised people, but are a danger to people who are not immunised. These include people who are particularly vulnerable to infectious disease, such as people with weakened immune systems due to conditions, such as cancer and HIV infections, the elderly, and very young babies.
When immunisation rates are high, an infection is unlikely to spread through a population. This 'herd immunity' serves as protection for the vulnerable parts of society.
The ultimate goal of a vaccination program is to completely eradicate the infectious organism, freeing humanity from its burden. This has been attained with smallpox, meaning that smallpox vaccination is no longer needed for anyone.
A few other diseases are headed that way (notably polio). However, for this to happen, nearly all of humanity must be immunised. This requires much effort and coordination, so is not easily achieved.
Childhood immunisation is now an established practice all over the world. Global vaccination rates have risen from about 20% in 1980 to 84% in 2013, with a corresponding drop in illness and death rates.  However, there are still children in the world who do not have access to vaccines. Immunisation programs in certain areas of South-East Asia and Africa in particular are finding it hard to reach every child.  
Failure to vaccinate is influenced by several factors, including:
- Shortages in funding;
- Logistical problems, and;
- Parental suspicion regarding immunisations.
Immunisation programs are especially difficult to run in areas undergoing civil strife or warfare.
Safety and parental concerns
When to delay or avoid vaccines (contraindications to vaccination)
Some children can be in increased danger of adverse effects. For these children, vaccination will be delayed or avoided. If your child has one of the following, speak to your doctor about upcoming immunisations:
- Specific allergies to particular vaccine components (eggs or egg protein, gelatine) or to previous vaccines;
- Congenital immune deficiencies, immunosuppressive medication, cancer treatments (chemotherapy or radiotherapy), or;
- The child is currently ill with fever.
Things that pose no obstacle to getting vaccinated include:
Adverse reactions to childhood vaccination
Like all injections, the immunisation injection is unpleasant, especially for babies and young children. Parents can help reduce the child's distress by comforting and distracting the child when the immediate pain of the injection has passed.
Common adverse reactions to vaccines include soreness at the injection site, mild fever and discomfort. However, very rarely, a child will exhibit an extreme and potentially life-threatening allergic reaction (anaphylaxis) to a vaccine. In such cases, immediate medical attention is required. Such reactions often show up within minutes after the injection. This is why children who have just been vaccinated are asked to remain in the clinic for about 15 minutes after their injection.
Some parents are concerned that vaccination can overburden the child's immune system and cause harm. These concerns are unfounded. From the first moment when it emerges into the world, a newborn baby is naturally exposed to a large load of microorganisms. The normal newborn's developing immune system is able to handle these microbial challenges effectively.
Vaccination is a small, generally insignificant addition to this process. Vaccines are effective not because they place any great burden on the immune system, but because they use the immune system's natural ability to remember specific infections.
An alleged link between MMR vaccination and the development of autism has been thoroughly investigated and repeatedly found to be false. Despite overwhelming evidence to the contrary, some parents remain suspicious of the MMR vaccine (and often vaccinations in general). This has led to a decline in vaccination rates in some areas of developed countries; subsequent outbreaks of vaccine-preventable disease often follow. Any such concerns should be discussed with a doctor before deciding not to vaccinate.