WASHINGTON — Executives from five COVID-19 vaccine manufacturers told Congress Tuesday that they expect to significantly boost the number of shots delivered to states in the coming weeks.

Pfizer will increase weekly shipments to more than 13 million doses by mid-March, an increase from the 4 to 5 million doses shipped weekly in early February, the company’s chief business officer, John Young, told a U.S. House panel.

Moderna, the other vaccine that has received federal authorization for emergency use, expects to double its monthly vaccine deliveries by April to more than 40 million doses per month.

If a third vaccine from Johnson & Johnson is authorized by the Food and Drug Administration, which could happen as soon as this weekend, the company says it can deliver enough single-dose shots by the end of March to vaccinate more than 20 million Americans.

Those anticipated boosts in production would ease a bottleneck in the national effort to vaccinate Americans: The Biden administration is frantically seeking ways to distribute more doses to state public health officials, who say they have the capacity to get more shots into arms than they currently are administering.

Pfizer — whose COVID-19 vaccine was the first to receive FDA emergency authorization — had shipped 40 million vaccine doses as of mid-February. Moderna’s president, Dr. Stephen Hoge, said the company had delivered 54 million doses as of last week.

Both companies say they are on track to deliver 300 million doses each by the end of July.

More doses in each vial

Officials for Pfizer and Moderna said they’ve sought to boost output by adding doses to each vial, increasing batch sizes, and adding production lines to their manufacturing sites.

“We recognize the need to vaccinate more people, more quickly, and have worked hard to significantly increase production,” Young said during Tuesday’s hearing of the House Energy and Commerce Committee’s oversight panel.

Rep. Diana DeGette, (D-Colo.), who chairs the oversight subcommittee, commended the vaccine manufacturers for their efforts, but noted that many of the companies testifying Tuesday received “significant federal investments” to build their manufacturing capacity and ensure vaccines could be rolled out immediately.

“Frankly, we still face a lack of vaccine supply to meet current demand,” DeGette said.

Additional doses could be on the way soon if the FDA gives emergency authorization to the Johnson & Johnson vaccine, which goes before an agency panel on Friday. Once the company receives the green light, 4 million doses could be shipped immediately, said Dr. Richard Nettles, vice president of U.S. medical affairs.

A vaccine from U.K.-based drug company AstraZeneca is still in clinical trials, but company officials said that if emergency use is granted, up to 50 million doses could be available by the end of April.

Another vaccine from Maryland-based Novavax could boost availability by another 100 million doses by the end of June.

Effectiveness in teens

More data is on the way regarding how effective the vaccines are for teenagers. Officials from Pfizer and Moderna said they are currently studying the effectiveness in those as young as 12 years old.

Amid concerns about new variants of the virus now circulating in the U.S., Young said Pfizer has seen “no real world evidence” so far to indicate that its vaccine is less effective against new variants. But both Pfizer and Moderna officials said they are studying the need for any booster shots.

As for looming concerns about whether the vaccines reduce asymptomatic transmission of the virus and how long it will offer protection from infection, the manufacturers said those answers will require further study.

“Unfortunately, the only real way we will know about the duration of that protection is over time,” Hoge said.

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This story is provided by Ohio Capital Journal, a part of States Newsroom, a national 501 (c)(3) nonprofit. See the original story here.