Shares of Vical ( VICL) were among the best-performing health-related stocks Friday, climbing 14% after the biotechnology company said its influenza vaccine protected mice against two different strains of human flu virus.

"The study was part of the company's program to develop a DNA vaccine that could ultimately protect humans against emerging strains of avian flu that could cause a pandemic," the company said. Vical said that Vaxfectin-formulated vaccines showed strategically superior protection in mice, especially at low doses, against two lethal strains of human influenza. The company's program has moved ahead to testing in mice and ferrets with the H5N1 strain of the bird flu. Results should be available during the second half of 2005. Shares were trading up 73 cents to $6.12.

American Oriental Bioengineering ( AOB) fell 3% even after the producer of pharmaceutical and nutraceutical products posted higher fourth-quarter results. The company earned $4.2 million, or 8 cents a share, on revenue of $19.8 million. During the year-earlier period, the company earned $2.8 million, or 8 cents a share, on revenue of $12.7 million. The company attributed the big jump in sales to growth to its plant-based products.

"We continue to grow out top line results by further expanding our distribution channels and product offering while increasing consumer awareness surrounding the benefits of traditional Chinese herbal remedies," the company said. Shares, which had jumped 16% since the beginning of the week, were recently down 16 cents to $5.07.

Shares of ( DIET) fell 4% after the company, which operates an online diet and health site, announced the resignation of its chief executive. The company said that Ciaran McCourt's resignation was due to "personal reasons." Robert Hamilton, chief financial officer, will assume McCourt's position on an interim basis.

eDiets also backed its first-quarter and full-year sales guidance. The company continues to project first-quarter sales growth of 4% to 6%, while it expects 2006 sales growth of 8% to 10%. For the full year, the company expects to post earnings that will be at least double that of earnings in 2005. Shares were down 21 cents to $5.29.

Novavax ( NVAX) fell modestly after the company said that bond holders chose to convert $7 million in outstanding senior convertible notes into nearly 1.3 million shares of stock at a price of $5.46 a share. The conversion reduced the amount of outstanding notes due July 15, 2009 to $22 million. Factoring in the conversion, the company now has some 61.3 million outstanding shares. Shares were trading down 11 cents to $8.07.

Shares of Merit Medical ( MMSI) fell 9% after the maker of syringes and other disposable medical devices warned that first-quarter earnings would be below expectations. The company sees earnings of 8 cents to 10 cents a share, including stock-based compensation costs, Analysts polled by Thomson First Call project earnings of 14 cents a share. The company anticipates sales of about $45 million, compared with analysts' estimate of $44.7 million. The company sees full-year earnings of 41 cents to 45 cents a share, including 3 cents a share in stock-based compensation costs. The company predicts sales of $185 million to $189 million. Analysts project earnings of 64 cents a share on sales of $187.7 million.

"We know the challenges of integrating our expanded capacity, newly released products, additional sales people and acquisitions, which in some ways are similar to the challenges we faced in early 2001," Merit said. "Now that we have these investments in place, we believe we can move forward and begin to see operational improvements which will enhance our future profitability." Shares were trading down $1.17 to $11.99.

Other health care volume movers included Pfizer ( PFE), up 2 cents to $25.22; Boston Scientific ( BSX), down 20 cents to $23.12; Generex Biotechnology ( GNBT), down 13 cents to $3.07; UnitedHealth Group ( UNH), down 64 cents to $55.62; Johnson & Johnson ( JNJ), down 4 cents to $59.31; Amgen ( AMGN), up 34 cents to $72.96; Bristol-Myers Squibb ( BMY), down 29 cents to $24.66; Elan ( ELN), down 36 cents to $14.40; Merck ( MRK), down 42 cents to $35.19; and Schering-Plough ( SGP), down 16 cents to $19.06.