The following editorial appeared in Sunday's Washington Post: With cases numbering more than 59,000 across 110 countries, Margaret Chan of the World Health Organization has declared a swine flu pandemic. 'The world is moving into the early days of its first influenza pandemic in the 21st century,' Dr. Chan said from Geneva, where she is the WHO's director general. 'The virus is now unstoppable.' Chilling words, but no cause for panic. Here are some things to keep in mind. The WHO Phase 6 designation, the highest alert for the global organization, is a recognition of the spread of the H1N1 virus, not the severity of the pandemic. Dr. Chan described the danger posed by swine flu as 'moderate.' The U.S. Department of Health and Human Services has characterized the flu cases in this country as 'less severe' than thought. So far, there have been 263 deaths worldwide, including 87 in the United States. According to the WHO, seasonal flu kills 250,000 to 500,000 people globally. In the United States, there are about 36,000 deaths a year. The 1968 Hong Kong flu pandemic killed 1 million people worldwide. The Obama administration has taken the proper approach from the outset. It has urged Americans to take precautions (stay home if you're sick, cover your sneezes, wash your hands) while preparing for the possibility that this new form of swine flu could mutate into something more virulent. Antiviral medication has been moved from federal stockpiles to the states. Vaccine development has begun. There are discussions with state and local authorities to plan for an immunization campaign should the need arise. Pandemics are serious, and there's no telling how this new strain of swine flu might change. All eyes are on the Southern Hemisphere, where it's winter and flu season is just beginning. Health authorities should remain vigilant and continue to keep the public informed. But the pandemic declaration is no reason to raid the drugstore for Tamiflu. 