The pork lobby is calling it H1N1. The Israelis have suggested the slightly more kosher Mexican Flu. Whatever you call swine flu, prevention still requires lots of handwashing, handkerchiefs and a total quarantine for anyone spotted buying Tylenol Cold and Flu at CVS.

According to grandma-in-chief Obama, that ought to keep the body healthy. But what about your portfolio? In a panic over the effects of a possible pandemic, the markets trembled world-wide. Pork futures fell, pharma stocks soared, and the fragile rally wobbled on fears that tourism, transportation and trade would be next to fall ill.

Stop squealing, analysts say. Any action at this point is speculation, says Sherry Cooper, chief economist at BMO Capital Markets in Toronto and co-author of that firm s 2005 An Investor s Guide to Avian Flu. The markets often overreact to this kind of news, in ways that make little sense. So do governments: Several countries have banned U.S. pork product imports, even though you don t get swine flu from, say, bacon.

And there s little historical data to guide us. Cooper points out that there have only been three global pandemics in the last 100 years too little data to draw any conclusions about a market effect. A Fidelity report backs her up: In looking at several flu outbreaks over the last 100 years, the fund firm found that market reaction varied unpredictably. The S&P 500 rose in 1968 and 1969, the years of the Hong Kong flu pandemic. In 2003, fears about SARS triggered a short-term drop, but markets finished up for the year. And often, the researchers found, other circumstances had a much greater effect on the markets. For example, Avian flu first triggered global concern in 1997 but the markets were more concerned with the Asian financial crisis, and then the ensuing Russian debt default and the implosion of Long-Term Capital Management.

So unless you re running a fever or planning a trip to Cancun there s little need to panic. And even the markets have shown at least some restraint: Harley Davidson (HOG) is up 12% this week.