Vaccines and Antivirals

Won't there be a vaccine to prevent pandemic influenza?

Influenza vaccines have to be made specifically for the particular virus causing an epidemic or pandemic. That is why the annual influenza vaccine changes each year. The vaccines also take several months to produce. Steps will be taken to produce a vaccine to protect against a new pandemic strain of influenza as quickly as possible, but a vaccine is unlikely to be available for the first wave of the illness.

Depending on the timing of the second wave of an influenza pandemic, scientists may be able to develop a vaccine so that people can get vaccinated. Preparation and research are already underway, which should help towards making a vaccine available as quickly as possible.

Aren't there drugs to treat pandemic influenza?

There are antiviral drugs that may be effective in treating pandemic influenza, but their use before or during a pandemic is not straightforward. Canada is taking steps to ensure that they are available. In the event of a pandemic, they will be used in the most effective way, based on how the disease develops.

Antivirals

Antiviral drugs can be used to treat pandemic influenza but their use has several limitations:

To be effective, they have to be given very quickly after symptoms start.
It would not be possible to give everybody antiviral drugs, and some will not need them.
It is also difficult to identify those groups of people who will develop more serious illness and who need antivirals the most.
It is impossible to measure the effectiveness of these drugs until the virus is circulating.
The pandemic influenza virus may develop resistance to the antiviral drugs.
We are already building a stockpile of antiviral drugs in Canada.
How many people we can treat will depend on when an influenza pandemic occurs.

What are antiviral drugs?

Antiviral drugs are special medicines for the treatment of certain viral infections. These drugs are likely to play an important role in treating pandemic influenza. Treatment with antiviral drugs can be expected to shorten the duration of the disease, alleviate symptoms, and reduce complications and serious illness. They can also be used to prevent influenza, particularly in the early stages of an influenza pandemic.

Does Canada have a stockpile of antiviral drugs?

Yes. Canada has a stockpile of antiviral drugs for emergency use and is building this up in case of an influenza pandemic.

Do antivirals have side effects?

Maybe. The antivirals that are likely to be of most use in a pandemic are generally well tolerated, but on occasion they can cause nausea and vomiting.

Why don't we make a vaccine against pandemic influenza now?

The virus will be new and not predictable in the way that ordinary influenza viruses are. Preparatory work is being undertaken to be in the best possible position to produce vaccine against a pandemic strain as quickly as possible when the need arises. But development of a vaccine will take time. A vaccine will not be available in the early stages of a pandemic.

How long would a vaccine take to produce?

About four to six months. There may be further delays due to unexpected technical difficulties. Once the virus has been identified and a suitable vaccine developed, then large-scale production will begin as quickly as possible.

Can we be sure Canada will be able to obtain enough vaccine for its own needs?

We will need more vaccine than we would usually use for annual vaccinations. Canada is therefore discussing its requirements with manufacturers.

Does this mean that certain people will get the vaccine before others?

Most likely. Priority may have to be given to certain groups. Health-care workers and key workers in other essential services may need to be vaccinated first, because we will need to maintain health and other essential services. Those groups most at risk of serious illness will be next to receive the vaccine as supplies increase.

Who will make the decision on prioritizing?

The government will make the decision based on advice from the Public Health Agency of Canada, medical, clinical, and public health experts, ethicists, and emergency planners.