Novavax Inc. (NVAX) shares climbed sharply Tuesday as investors reacted to concerning news about respiratory illness activity across the country. The biotech vaccine maker found itself among the day's top performers as health officials painted a picture of a prolonged and severe flu season.

The Respiratory Illness Landscape

On Friday, January 9, 2026, the CDC delivered some sobering statistics. Respiratory illness activity isn't just elevated—it remains high nationwide with no signs of letting up soon. Flu cases are widespread and expected to stay that way for several more weeks. RSV levels are also running high in many regions, particularly affecting young children, with emergency room visits and hospitalizations climbing among kids ages 0-4. COVID-19 activity is still relatively low but showing an upward trend.

Here's where it gets interesting: The CDC classified the 2025-26 flu season as "moderately severe" for the first time. The numbers tell the story—at least 11 million illnesses, 120,000 hospitalizations, and 5,000 deaths so far this season. Compare that to the week ended December 28, 2024, when we saw at least 5.3 million illnesses, 63,000 hospitalizations, and 2,700 deaths.

Some metrics dipped or leveled off this week, but the CDC cautions against reading too much into that. Holiday schedules likely affected when people sought care and how cases were reported, not an actual peak in flu season. The agency expects flu activity to remain elevated for several more weeks.

This sustained respiratory illness environment is putting vaccine manufacturers back in the spotlight as the season drags on.

What Moderna's Guidance Tells Us

The respiratory illness environment isn't just theoretical—it's affecting how vaccine makers think about their business. Moderna (MRNA) recently tightened its outlook, now expecting about $1.9 billion in 2025 revenue. The company also trimmed its expected 2025 operating expenses by $200 million and projects its year-end cash balance around $8.1 billion, providing more financial flexibility.

Looking forward, Moderna still plans for up to 10% revenue growth in 2026 while continuing cost reductions. The company is preparing for what could be a pivotal pipeline year, with potential first approvals for its flu and flu/COVID combo vaccines, along with key trial results in oncology, rare diseases, and infectious diseases. These developments could help diversify beyond COVID-19 and strengthen its position during a year when respiratory illness remains a major public health concern.

The Technical Picture for Novavax

From a technical standpoint, Novavax is showing some compelling signals. The stock is trading significantly above its key moving averages—24.8% above its 20-day SMA and 23.9% above its 50-day SMA. That positioning suggests bullish momentum with potential for continued upward movement.

The RSI sits at 64.94, which places it in neutral territory but approaching overbought conditions. There's positive momentum here, but traders should watch for a potential pullback if RSI crosses above 70.

The MACD is above its signal line, indicating bullish momentum and suggesting the current trend may have staying power. Key support sits at $7.50, while resistance is at $9.00. A break above resistance could signal a continuation of the uptrend, while dropping below support might indicate a reversal.

Worth noting: A death cross occurred in December when the 50-day SMA crossed below the 200-day SMA. This typically signals a bearish trend, so traders should keep this in mind when evaluating future movements.

Over the 12-month period, NVAX has gained just 0.81%, reflecting a relatively flat longer-term trend. While there may be short-term volatility, the stock hasn't established a strong upward trajectory over the past year.

Currently, the stock is positioned at 65.1% of its 52-week range, sitting closer to the high of $10.64 than the low of $5.01. This suggests potential for further gains, though traders should remain cautious of overbought conditions.

NVAX Price Action: Novavax shares were up 16.22% at $39.33 at the time of publication on Tuesday.