Why immunization is important

Immunization is one of the best ways to protect yourself, your children and future generations from infectious diseases. When you keep your family’s vaccinations up to date, you are not only looking after your own household, you are also helping to protect vulnerable people in your community. The more people who are vaccinated, the fewer people become infected, and the harder it is for a disease to spread.

Immunization saves lives#

As recently as the 1950s, thousands of children died every year from infectious diseases. Today it is rare for anyone to die from many of these diseases, thanks to the major vaccination programs introduced in the following decades and continued ever since.

How do vaccinations work?#

A vaccine builds up your protection against an infection before you ever come into contact with it. In effect, it is like being exposed to the disease without suffering the actual illness.

If you meet the infection after being vaccinated, your body is already prepared to fight it off. You either avoid the disease entirely or experience only a mild case.

Unlike some other approaches that have been proposed, vaccinations are rigorously tested to demonstrate that they are safe and effective at protecting against infectious disease.

What about people who cannot be immunized?#

Some people in the community cannot be vaccinated, perhaps because they are too young or too unwell. You can help protect these vulnerable people by keeping your own family’s vaccinations up to date.

When enough people in a community are vaccinated, the spread of a disease slows down or stops completely, because the disease can no longer move easily from person to person. This is called herd immunity, or community immunity, and it protects friends, family and others, especially those who cannot be immunized themselves.

Infectious diseases are still with us#

Many infectious diseases are now rare or no longer circulating, thanks to vaccination. But outbreaks still happen around the world. Some examples include:

• COVID-19, a relatively new disease that researchers are still learning about, including its long-term effects
• Diseases such as flu, chickenpox, whooping cough and measles, which still cause occasional outbreaks, often when introduced from elsewhere, and which could return strongly if people stop vaccinating
• Zika virus, declared an international public health emergency by the World Health Organization (WHO) in February 2016 following outbreaks in the Americas, with mosquito-transmitted infection reported across many countries and territories
• Ebola virus disease, which mainly affects parts of Africa and continues to cause outbreaks
• HIV/AIDS, first identified in 1981 and now found worldwide, with tens of millions of people living with the virus; there is still no cure, but current treatments allow people to live long and healthy lives

There are no vaccines yet for Zika, Ebola or HIV/AIDS, but research is underway.

How new vaccines are developed#

It can take a long time to develop a new vaccine. The process is rigorous, and a vaccine continues to be monitored even after it is in use, to make sure it stays safe and effective.

A new vaccine goes through many phases, including research and discovery, pre-clinical testing, clinical testing and regulatory approval. Once approved, it is manufactured and shipped to where it is needed. In some circumstances, extra resources, parallel clinical trials and funding can speed up this development.

After a vaccine is introduced, it is closely watched through ongoing trials and surveillance to confirm that it is effective and safe. Regional and national surveillance systems actively look for any adverse events following immunization, because occasionally unexpected side effects only become apparent once a vaccine is in wide use.

Some vaccines, such as the flu vaccine, need to be updated every year to respond to changing strains. For these updates the process is compressed so the vaccine can be ready in time.

Immunization surveillance#

To keep communities safe, health authorities need a complete picture of immunization across the population. Immunization surveillance involves gathering and analysing information about immunization programs and about vaccine-preventable diseases. Many countries have an official body responsible for this work.

Who needs to be vaccinated?#

The answer is simple: almost everyone. There are some exceptions, usually people with a serious medical condition, such as a weakened immune system. But never decide against immunization without checking with your doctor first.

Your doctor can advise which vaccinations you need based on your health condition, age, lifestyle and occupation. Vaccination is particularly recommended if you:

• Are a newborn or young child, or have a new baby
• Are pregnant or planning a pregnancy
• Care for very young babies, for example as a parent, grandparent or carer
• Are an older person
• Belong to a group that is medically at higher risk
• Have certain medical conditions, such as asthma
• Plan to travel internationally

If you find you are not up to date, your doctor can tell you about catch-up and booster doses.

Where to get more information#

The best place to start is with your doctor. You can also ask a child health nurse or paediatrician.

There is plenty of information online as well, but stick to reliable sources, such as:

• Your regional or national health authority
• Your own health professional

If you are ever unsure about which immunizations you need, talk to your doctor.

Key points#

• Vaccination is like being exposed to a disease without suffering the actual illness, so your body is ready to fight it off
• Some people cannot be vaccinated because they are too young or too sick, and herd immunity helps protect them
• Getting vaccinated plays an important role in keeping both you and your community safe
• Diseases that are now rare can return if people stop vaccinating, and outbreaks still occur around the world
• There is still no cure for some infections, but current treatments can allow people to live long and healthy lives

Where to get help#