## Do seasonal flu vaccines also work effectively against pandemic influenza A (H1N1)?

A Seasonal flu vaccine is supposed to be effective against seasonal influenza. If you intend to receive a seasonal flu vaccine (senior citizens should preferably receive a seasonal flu vaccine), it is recommended to do so by mid-December. A domestically produced pandemic influenza A (H1N1) vaccine and a seasonal flu vaccine can be received at the same time if doctors consider it necessary.

## Do people who have been infected once with pandemic influenza A (H1N1) need to receive a pandemic influenza A (H1N1) vaccine?

A Generally, people who have been infected once with pandemic influenza A (H1N1) become immune. Therefore, they do not have to get vaccinated. However, only people whose infection with the pandemic influenza A (H1N1) virus was confirmed through a special inspection (such as PCR inspection) are considered to have surely been infected with pandemic influenza A (H1N1).

## Are people with low priority unable to receive a pandemic influenza A (H1N1) vaccine, and do those with high priority have to receive it?

A It is required to ensure there is enough vaccine for all people who want to get vaccinated, in addition to those with high priority. After all the people with high priority have been vaccinated, vaccination for other people will be conducted appropriately based on the situation of the epidemic, the number of people vaccinated and the vaccine supply. Even those with high priority are not necessarily required to get vaccinated.

## Q What are the differences between domestically produced vaccines and foreign vaccines?

Foreign vaccines differ from domestically produced vaccines in that: (i) imported vaccines have never been used in Japan; (ii) imported vaccines contain an adjuvant (immunity auxiliary substance) that has never been used in Japan; (iii) some imported vaccines are produced by the cell culture method, which has never been used in Japan (domestic vaccines are all produced by the egg culture method); (iv) an imported vaccine is injected into muscle (a domestic vaccine is injected below the skin); and (v) the vaccine dose for young children differs. On the premise that imported vaccines have been approved in their respective countries, their effectiveness and safety shall be confirmed based on various data before vaccination begins.

## For inquiries :

Ministry of Health, Labour and Welfare Website :

http://www.mhlw.go.jp/bunya/kenkou/kekkaku-kansenshou04/index.html

# Vaccination against

tentative translation

# Pandemic Influenza A (H1N1)

## What you need to know

It has been confirmed that flu vaccines have an effect that prevents an increase in the severity of influenza and can also prevent death from influenza. However, they are not versatile and worldwide production is limited. This pamphlet contains what you should know about the proper use of limited vaccines.

## Characteristics of Pandemic Influenza A (H1N1)

Pandemic influenza A (H1N1) is highly contagious, but many people who have been infected have recovered without becoming seriously ill. Antiviral drugs (Tamiflu and Relenza) are effective against pandemic influenza A (H1N1). However, those with underlying diseases (diabetes, asthma and so on) and pregnant women are likely to have serious flu complications and need to be more careful.

## Significance of vaccination

The vaccines that will be used for this vaccination program are the first ones ever produced for pandemic influenza A (H1N1), but various data available so far have revealed that there is clear evidence of serious or fatal health complications for some people who catch this flu. However, as the effect that prevents infection has not yet been proven, vaccinated people may also become infected with the flu.

## Effectiveness and safety of the Pandemic Influenza A (H1N1) vaccines

Domestically produced vaccines are expected to be effective to some extent and are believed to be as safe as the seasonal flu vaccines that have long been used in Japan. Regarding imported vaccines, on the premise that they have been approved in the respective country(ies), their effectiveness and safety shall be confirmed based on various data before vaccination starts.

Be sure to consider the effectiveness and risks before getting vaccinated.

Vaccination has such advantages as protecting serious or fatal complications of pandemic influenza A(H1N1) from many people, but it may sometimes cause some side effects such as swelling or fever. In rare cases, even serious side effects can be caused. Whether or not to get vaccinated should be determined on an individual basis, with a full understanding of such risks and benefits. Information will be provided promptly by the administration.