Shares of

Candela

( CLZR) were among the worst-performing health-related stocks Thursday, falling 12% after the company posted fourth-quarter results that fell below Wall Street forecasts.

The maker of medical lasers reported earnings of $3.2 million, or 14 cents a share, on sales of $38.6 million. Analysts polled by Thomson First Call were expecting earnings of 17 cents a share on sales of $39.7 million. A year ago, the company earned $4.3 million, or 19 cents a share, on sales of $34.2 million. For the entire year, the company reported earnings from continuing operations of $6.5 million, or 28 cents a share, on sales of $123.9 million. Shares were trading down $1.30 to $9.93.

Patterson

(PDCO) - Get Report

fell 5% after the supplier of dental products reported first-quarter earnings and sales that fell below expectations. The company earned $42.9 million, or 31 cents a share, on sales of $595.8 million. Analysts were expecting earnings of 32 cents a share on sales of $624.3 million. A year ago, the company earned $40.8 million, or 29 cents a share, on sales of $577.9 million. Patterson said the earnings shortfall was the result of below-plan growth of basic dental equipment -- including lights, chairs and units. Shares were trading down $2.06 to $39.63.

Shares of

Emdeon

(HLTH)

, which recently changed its name from WebMD, fell 6% after the company priced $300 million of 3.125% convertible senior notes due 2025. Proceeds from the 20-year notes will be used to fund general corporate purposes. Shares were trading down 67 cents to $10.86.

Novavax

(NVAX) - Get Report

rose 35% after the company reported positive preclinical results from its Virus-Like Particle influenza vaccine. The results, published in the Aug. 15 online edition of the journal

Vaccine

, "demonstrates that a H9N2 influenza virus (avian flu) vaccine produced with the company's proprietary VLP technology is effective in protecting animals when challenged with live H9N2 virus," the company said. Ultimately, the company said it plans to advance its VLP technology into clinical trials with both seasonal and pandemic versions of influenza VLP vaccines. Shares were trading up 33 cents to $1.28.

Shares of

Nastech Pharmaceutical

( NSTK) rose 3% after the company priced 1.725 million shares at $13.50 apiece, representing just a small discount to Wednesday's closing price of $13.61. The offering, which is expected to result in gross proceeds of $23.3 million, was made as part of a shelf registration statement that became effective in October of last year. Earlier this month, Nastech withdrew an offering for 1.5 million shares, citing unfavorable market conditions. At the time, Nastech said that it would continue to evaluate market conditions and other financing opportunities. Shares were recently trading up 45 cents to $14.05.

Other health-care volume movers included

Pfizer

(PFE) - Get Report

, down 7 cents to $24.99;

Amylin Pharmaceuticals

( AMLN), up $1.04 to $29.90;

Elan

(ELN)

, up 27 cents to $8.51;

Merck

(MRK) - Get Report

, down 2 cents to $27.81;

Guidant

( GDT), down 58 cents to $71.07;

Johnson & Johnson

(JNJ) - Get Report

, up 41 cents to $62.66;

Amgen

(AMGN) - Get Report

, up 77 cents to $79.51;

Bristol-Myers Squibb

(BMY) - Get Report

, down 11 cents to $24.15; and

Schering-Plough

( SGP), up 8 cents to $20.80.