Epidemiological risk factors that should raise suspicion of swine influenza A(H1N1) include:
• Close contact# to a confirmed case of swine influenza A(H1N1) virus infection while the case was ill

• Recent travel to an area where there are confirmed cases of swine influenza A (H1N1)

#Close contact: having cared for, lived with, or had direct contact with respiratory secretions or body fluids of a probable or confirmed case of swine influenza A(H1N1).

Member States reporting cases of swine influenza A(H1N1) virus infection for the first time

As soon as a the National IHR Focal Point or competent national public health authority notifies WHO of the first laboratory‐confirmed or probable case(s) of swine influenza A(H1N1), WHO will make available the case summary form and database for the recording of detailed clinical, laboratory and epidemiological data in accordance with WHO pandemic surveillance guidelines.

Member States where cases of swine influenza A(H1N1) virus infection have already been reported

Until further notice, the National IHR Focal Points or competent national public health authorities should report to WHO all probable and confirmed cases on a daily basis. Deaths should be reported for both probable and confirmed cases.

WHO will present the cumulative number of cases for global reporting back to Member States and the public. This activity will only continue for the initial period of data collection.

In order to understand the severity of the disease it is very important that comprehensive data collection and follow up is carried out for all probable and confirmed cases of swine influenza A(H1N1) virus infection. WHO’s data requirements are detailed in the Global Surveillance during an Influenza Pandemic Version 1 Updated draft April 2009 (Comprehensive Assessment, Clinical characteristics: Database of information for 100 cases). Many countries and territories will have already developed questionnaires for influenza A(H5N1) related investigation. These can be adapted and used for the investigation of individuals for whom swine influenza A(H1N1) virus infection is considered.

Confirmed and probable cases reported are to be attributed to the country or territory in which they are currently located or where they have died. Changes in case classification from probable to confirmed, as well as determination of the final outcome of the disease, should be signalled when reporting and will be reflected in the updates to be published by WHO.

The reported case‐based data will be used by WHO to compile daily global surveillance summaries. These summaries will be presented on the WHO headquarters website (http://www.who.int) as the latest cumulative case count and maps of geographical distribution.

Access to Laboratory Confirmation

Countries without current capacity to confirm swine influenza A(H1N1) should contact WHO to arrange access to a laboratory with this capability.

(WHO April 28, 2009)