Antivirals & vaccines

Antivirals

Medicines known as antivirals may have some effectiveness in preventing the development of infection in people exposed to the influenza virus. When used as a treatment, antivirals can reduce the duration of symptoms and illness.

To be effective, antivirals have to be administered either before or soon after a person shows symptoms. The influenza virus can also adapt to become resistant to antivirals used against it, in the same way as some bacteria have adapted to resist antibiotics.

It is therefore important to understand that the use of antiviral medication in a pandemic will depend on the phase of the outbreak in Australia, and will be carefully monitored to ensure effective use as part of the broader strategy to reduce illness, contain the spread and minimise the impact of a pandemic.

The Australian Government has developed a significant stockpile of antivirals to be used in the event of a pandemic. The Australian Health Management Plan for Pandemic Influenza 2009 details the Government's strategy for the use of antivirals.

The details of antiviral use described below may be modified at the time as evidence comes in about a range of factors, such as:

• the effectiveness of antivirals in preventing infection and treating cases (including any evidence of antiviral resistance)
• the effectiveness of candidate and customised pandemic vaccine
• the protection offered by natural infection
• the availability of resources
• the anticipated length of time until the customised pandemic vaccine will become available.

Antivirals use

Antivirals usage includes:

• treatment of cases when clinically appropriate
• post exposure prophylaxis to reduce the risk of infection in people who have not been able to avoid close unprotected contact with an infectious case, such as:
  • in health care and some other occupational settings
  • in households
  • in the community (e.g. workplace) in the CONTAIN phase.
• pre-exposure prophylaxis to reduce the likelihood of infection when:
  • persons are exposed to an aerosol generating procedure on a case
  • there is likely to be ongoing re-exposure to known infectious cases for example, in influenza services.

If possible, (depending on resource availability) the Australian Government will consider reserving some stocks of antivirals for possible second wave.

Top of Page

Vaccines

A vaccine that gives good protection against a pandemic influenza virus can only be developed after the new virus strain appears, and therefore may take several months to produce, and will initially be in short supply.

The Australian Government has arrangements in place to develop a suitable vaccine as soon as such a virus emerges.

Vaccine manufacturers have been contracted to ensure that if an influenza pandemic occurs, enough vaccine for all Australians will be produced. However, the vaccine may take several months to produce. Once a sufficient supply of the vaccine has been manufactured, all Australians will be able to receive the vaccine.

The seasonal flu vaccine will not protect against a new pandemic flu. Nevertheless, in the lead up to a pandemic, it will still be important to vaccinate high-risk groups against any seasonal strains of flu currently circulating. The pneumococcal vaccine is also important for the elderly, as it can prevent secondary pneumococcal pneumonia.

Vaccinations outside a pandemic

The annual seasonal influenza vaccine protects against seasonal influenza viruses, but will not protect against a new pandemic influenza strain. Seasonal flu vaccination can be administered to anyone who wishes to reduce the likelihood of becoming ill with seasonal influenza. However, annual vaccination is recommended for people who are at increased risk of flu-related complications. You should check with your doctor to ensure you are able to have the vaccine and that there are no contraindications for you such as some allergies.

The pneumococcal vaccine is also important for people who are at risk of contracting pneumococcal infection after they become infected with the seasonal or pandemic strain of influenza. Your doctor can provide further advice about whether you should receive these vaccines.

The National Immunisation Program Schedule (external link) outlines the recommended and fully funded vaccine plan by age group.

People who have a severe allergic response (anaphylaxis) to eggs should not be given the seasonal flu vaccine. This includes people who soon after ingesting eggs develop swelling of the lips or tongue, or experience acute respiratory distress or collapse. People with severe allergy to any of the product components should also not be given the flu vaccine. Ask your doctor if you think you could be one of these people.

People with minor illnesses can still get the flu vaccine. However, if you have a fever (temperature of 38.5ºC or higher) you should wait until it has resolved.

The risk and benefits of vaccination should be discussed with your doctor, especially if you have had significant reactions to other vaccines in the past.

This information is current for 04 February, 2012
This information was issued on 06 January, 2011