Australia leads the world in child immunization coverage

Although Australia is preparing for a deadly flu season, it can be comforted by the fact that nearly 95% of five-year-old Australian children are almost completely immune to deadly childhood diseases, according to the latest report.

Globally, vaccine coverage has reached about 85%, making it a remarkable achievement that deserves to be imitated at all levels.

Vaccine preventable childhood diseases that are covered by the standard include diphtheria, polio, whooping cough, tetanus, and the virus that causes infant meningitis, Hemophilus influenza B, as well as hepatitis B virus. Other vaccines included in the program include mumps, measles and rubella viruses.

Universal vaccination of children

Universal immunization of children is widely touted as a simple, safe and effective way to prevent these diseases in children before they are exposed to it. Vaccination works not only by protecting the person who receives the vaccine, but also by inciting a phenomenon called herd immunity or community immunity. This is defined as the production of resistance to the spread of communicable diseases within a population by the presence of immunity to the disease concerned in a very high percentage of individuals within the population. Thus, vaccination helps the entire population once coverage rates have reached and are maintained at a sufficiently high level.

Community immunity provides a particularly important type of protection for newborns, the elderly, chemotherapeutics, people with impaired immunodeficiency, and those who are ill and can not be immunized, but at an increased risk of infection. However, collective immunity does not protect the individual against vaccine-preventable diseases as effectively as immunization, and should not be promoted instead of being immunized.

All vaccine-preventable diseases can not be protected by collective immunity because tetanus, for example, comes from environmental spores of tetanus bacillus rather than other people. For these diseases, individual vaccination is the only way to ensure that the child is protected.

How vaccination works

Immunization works by presenting a weakened form of molecules on the virus or bacteria that produce these diseases in the body before it is exposed to real germs. The presence of these molecules, called antigens, induces an immune response in the body, manifested by mild fever, tenderness and other benign local or systemic reactions. This is followed by storing the memory of these antigen data in the immune system, inside the memory cells, or B cells.

Faced with this infection, the body quickly enters a very specific and powerful mode of defense, as the B cells that store the relevant information multiply and transform into antibody factories. These produce specific antibodies, protein molecules that recognize the antigen and bind to the specific bacteria against which the body has been immunized. The bound antibody helps other immune cells to rapidly neutralize and destroy invading microbes and to contain the infection before the person gets sick. In most cases, the individual is not even aware of having been exposed to infection because of the speed and effectiveness of the immune response.

Australian model: worthy of emulation

Australian quarterly data shows that nearly 95% of five-year-olds have been fully immunized this year. Coverage is even higher, at almost 97%, among five-year-old Aboriginal children. Victoria and Tasmania are regions with exceptionally high rates of complete vaccination. More and more children are fully vaccinated at the age of one, two and five years throughout the country.

The importance of this uniform pattern of coverage is better understood when compared to countries such as the United Kingdom, where vaccination rates are high at the national level, but with large pockets of vaccine coverage. This leaves much room for the spread of contagious diseases and the emergence of local or regional epidemics, as was the case with measles in 2013 in Wales. Indeed, a non-immune person in those areas who is exposed to measles, for example, is likely to come in contact with many more non-immune individuals and to transmit the disease.

Australian Health Minister Greg Hunt congratulated the results, saying: "The latest figures show that the vast majority of parents hear the message about the benefits of vaccines and I am pleased that our public health campaigns and vaccination protect all Australians. "