Prevnar use in seniors is cost-effective now, CDC says. But will it last?

After meeting to discuss the use of Pfizer's($PFE) Prevnar 13 in adults 65 and older late last week, a CDC advisory committee isn't planning to vote on recommendation of the shot just yet. But when it does, it will have a few things to consider--including Prevnar's long-term cost effectiveness in that population--before giving it a nod.

The Advisory Committee on Immunization Practices (ACIP) figures immunizing seniors is cost-effective in the short term, according to ISI Group analyst Mark Schoenebaum. But in the long term? Possibly not, thanks to herd immunity. Because Prevnar is recommended for all children, fewer adults, too, are being sickened by the 13 types of pneumococcal bacteria that the vaccine protects against. And that effect will expand to protect more adults over the next several years, the CDC says.

"This vaccine clearly works," Schoenebaum said in an investor video. "Any person who gets it will have a lower chance of getting the infection. But if the chance of getting the infection at baseline without the vaccine is very, very, very low, as it appears it may be after herd immunity fully kicks in, the cost effectiveness of giving Prevnar to all adults over 65 years old isn't there, according to this committee."

Prevnar is already the top-selling vaccine in the world, and the $4.05 billion it raked in worldwide for 2013 is only projected to grow. But as Schoenebaum pointed out to investors, ACIP recommendation is key for expansion in the 65-plus crowd: Not only will physicians not use vaccines until they get the ACIP nod, but many payers won't cover them, either.

This is not the first time ACIP has weighed a Prevnar recommendation. Back in 2012, the committee examined the topic, but put further discussions off in order to wait for more data. Courtesy of Pfizer's CAPiTA trial, it has that now, and Schoenebaum said he predicts a vote at the committee's October meeting--if not sooner, to make sure the 2014-15 season is covered--will yield at least a recommendation for the near term.

"Given ACIP's opinion that the vaccine is clearly cost effective over the short term, it's hard for me to understand how the committee could not recommend universal use at least over the next few years," he wrote in a note.

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