Parents and doctors like to keep kids healthy, which is why Wyeth's (NYSE:WYE) Prevnar vaccine for infants and toddlers is a powerful draw. But yesterday, the drug maker announced a "temporary delay" in Prevnar shipments as it works to make some changes to its quality-control processes.

The vaccine is used to prevent pneumococcal infections in children, such as meningitis, pneumonia, and blood infections. It is included in the battery of immunizations for infants and toddlers, and there's no small amount of demand.

Over the last several years, Wyeth was unable to meet demand for the vaccine and ramped up production earlier this year, resulting in a significant boost of the product's sales in the third quarter. According to the company, the current delay is not expected to have an impact on Wyeth's financials.

Reuters reported that the move to upgrade quality assurance was voluntary and not the result of a Food and Drug Administration directive to straighten up. In Wyeth's press release on the matter, the company sought to comfort investors with assurances that this will not result in a shortage, and that this development does not imply any questions about the safety or effectiveness of the vaccine.

However, the delay does make one wonder: Why is this upgrade happening now instead of prior to the manufacturing ramp-up months ago?

Although the delay may not affect revenues for this $1 billion-per-year vaccine, it's disconcerting nonetheless. While stepping up quality control is certainly a case of better late than never, a delay before the season when illnesses crop up more frequently makes one wonder whether somebody dropped the ball.

This isn't the only distraction facing Wyeth's management. Just a few weeks ago, the company voiced the possibility that it may have to sock away some cash in case it faces new allegations related to its old weight-loss product, Fen-phen. And the company has partnered with MedImmune (NASDAQ:MEDI) on the Flu-Mist product, which looks like it could falter in its launch year due to a few hurdles such as a high price and losing its distribution deal with Wal-Mart (NYSE:WMT).

Wyeth's going to have to step carefully to avoid giving investors a shot of uncertainty.

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Alyce Lomax welcomes your feedback at alomax@fool.com.