Updated September 4, 2020:
This stamp is going back on sale. In response to a question from The Virtual Stamp Club, there will be no special collector servicing (i.e., postmarks) for the return to sale.

[press release]
Alzheimer’s Semipostal Fundraising Stamp Returning
Stamp Sales Resume, Oct. 5

WASHINGTON, DC — The U.S. Postal Service is resuming sale of the Alzheimer’s Semipostal fundraising stamp Oct. 5 resulting from rule changes announced in September 4th’s Federal Register.

The Semipostal Authorization Act grants the Postal Service authority to issue and sell semipostal fundraising stamps to advance causes deemed to be “in the national public interest and appropriate.”

Before the rule change, the Postal Service was permitted to offer only one semipostal stamp of its choosing for a two-year period, in addition to any semipostal stamps mandated by Congress. The change eliminates this restriction, allowing USPS to resume the sale of the Alzheimer’s semipostal stamp, which debuted in 2017.

The Federal Register’s Sept. 4 edition has more information.

The price of the stamp includes the First-Class Mail single-piece postage rate in effect at the time of purchase plus an amount to fund Alzheimer’s research. By law, revenue from sales of the Alzheimer’s Semipostal stamp — minus the postage paid and the reimbursement of reasonable costs incurred by the Postal Service — will be distributed to the National Institutes of Health, which is part of the U.S. Department of Health and Human Services.

Ethel Kessler served as art director for the stamp, while artist Matt Mahurin created the design.

Updated January 2, 2018: Scott Publishing has assigned this the catalogue number B6.

Updated November 24th: There is no Digital Color Postmark for this issue, but there is a pictorial hand cancel: It measures 2.99 by 1.08 inches.

Updated November 2nd:
[press release]
U.S. Postal Service Previews Alzheimer’s Semipostal Fundraising Stamp Image
Dedication to take place Nov. 30

WASHINGTON — The U.S. Postal Service has previewed the image of the Alzheimer’s Semipostal fundraising stamp.

It also announced the stamp will be dedicated at 10 a.m., Thursday, Nov. 30 at Johns Hopkins Asthma & Allergy Center Atrium, Johns Hopkins Bayview Medical Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224.

Available nationwide Nov. 30, the Alzheimer’s Semipostal stamp will be sold for 60 cents. The price includes the first-class single-piece postage rate in effect at the time of purchase plus an amount to fund Alzheimer’s research. By law, revenue from sales of the Alzheimer’s Semipostal stamp — minus the postage paid and the reimbursement of reasonable costs incurred by the Postal Service — will be distributed to the National Institutes of Health, which is part of the U.S. Department of Health and Human Services.

The event is free and open to the public. RSVP is required to attend the ceremony. Please RSVP at usps.com/alzheimers. Followers of the U.S. Postal Service’s Facebook page can view the first-day-of-issue ceremony live at facebook.com/USPS. Customers may pre-order the stamps at usps.com/shop in early November for delivery shortly after the Nov. 30 issuance. Please share the news on social media using the hashtag #AlzheimersStamp.

Postmaster General and Chief Executive Officer Megan J. Brennan will dedicate the stamp. In attendance will be Kathy Siggins of Mount Airy, MD, who followed the discretionary semipostal program criteria for submitting the stamp suggestion. Siggins’ husband succumbed to the disease in 1999.

The artwork is an illustration that first appeared on the 2008 42-cent Alzheimer’s Awareness stamp (shown on the right). It shows an older woman in profile with a caring hand on her shoulder with the suggestion of sunlight behind her and clouds in front of and below her. On the 2008 stamp, she was facing left; the artwork for this stamp shows her facing right to help differentiate between the two stamps. Stamp artist Matt Mahurin of Topanga Canyon, CA, worked under the direction of art director Ethel Kessler of Bethesda, MD.

The Semipostal Authorization Act, Pub. L. 106–253, grants the U.S. Postal Service discretionary authority to issue and sell semipostal fundraising stamps to advance such causes as it considers to be ‘‘in the national public interest and appropriate.’’ Under the program, the Postal Service intends to issue five semipostal fundraising stamps over a 10-year period, with each stamp to be sold for no more than two years. The Alzheimer’s Semipostal stamp is the first and will be followed by a Post-Traumatic Stress Disorder (PTSD) semipostal stamp to be issued in 2019. The next three discretionary semipostal stamps have not yet been determined.

Under the Act, the Postal Service will consider proposals for future semipostals until May 20, 2023. The Federal Register notice outlining this program can be found at the following url: https://www.gpo.gov/fdsys/pkg/FR-2016-04-20/pdf/2016-09081.pdf.

Proposals will only be considered if they meet all submission requirements and selection criteria. They may be submitted by mail to the following address:

Office of Stamp Services
Attn: Semipostal Discretionary Program
475 L’Enfant Plaza SW., Room 3300
Washington, DC 20260–3501

Suggestions may also be submitted in a single Adobe Acrobat (.pdf) file sent by email to semipostal@usps.gov. Indicate in the Subject Line: Semipostal Discretionary Program.
There are currently two semipostal stamps available for sale that has been mandated by Congress. These are the Breast Cancer Research Semipostal which has raised more than $86.1 million and the Save Vanishing Species Semipostal which has raised more than $4.3 million as of September 2017. Visit this link for additional information.

All postage stamps are available for purchase at Post Offices, online at usps.com, and by toll-free phone order at 1-800 STAMP-24.

The Postal Service receives no tax dollars for operating expenses and relies on the sale of postage, products and services to fund its operations.

Updated October 11th with information from the Postal Bulletin:
However, there is still no design, no date and no first-day city.

The U.S. Postal Service® will issue the Alzheimer’s semipostal stamp (Nondenominated, First-Class Mail® priced at 60 cents) in one design, in a pressure-sensitive adhesive (PSA) pane of 20 stamps (Item 564200). A November release date is anticipated for the stamp; more information will be announced as it becomes available. The Alzheimer’s semipostal stamp will appear in a future edition of the Postal Bulletin and must not be sold before the official first-day-of-issue.

Availability to Post Offices: Item 564200, Alzheimer’s Semipostal (Nondenominated, First-Class Mail priced at 60 cents) PSA Pane of 20 Stamps: Stamp Fulfillment Services (SFS) will  an automatic push distribution to Post Offices™ of a quantity to cover approximately 30 days of sales.

Sales Policy
As has been the case with current and previous semipostal stamp issues, all Post Offices must maintain a sufficient inventory level of this item until the stamp is officially withdrawn from sale. The stamp is well supported by a variety of organizations and individuals who expect that the stamp will be available at all Post Offices. If supplies run low, Post Offices must reorder additional quantities using normal ordering procedures.

Technical Specifications:

Issue: Alzheimer’s Semipostal Stamp
Item Number: 564200
Denomination & Type of Issue: Nondenominated, First-Class Mail (60 cents)
Format: Pane of 20 (1 design)
Series: N/A
Issue Date & City: TBD
Designer: Ethel Kessler, Bethesda, MD
Art Director: Ethel Kessler, Bethesda, MD
Typographer: Ethel Kessler, Bethesda, MD
Artist: Matt Mahurin
Modeler: Sandra Lane/Michelle Finn
Manufacturing Process: Offset, Microprint
Printer: Banknote Corporation of America
Printed at: Browns Summit, NC
Press Type: Alprinta 74
Stamps per Pane: 20
Print Quantity: 500,000,000 stamps
Paper Type: Phosphor Tagged Paper. Overall
Adhesive Type: Pressure-sensitive
Processed at: Banknote Corporation of America, Browns Summit NC
Colors: Cyan, Magenta, Yellow, Black, PMS 614/Beige, PMS 451/Brown
Stamp Orientation: Vertical
Image Area (w x h): 1.085 x 1.42 in./27.56 x 36.07 mm
Overall Size (w x h): 1.225 x 1.56 in./31.12 x 39.62 mm
Full Pane Size (w x h): 7.12 x 7.24 in./180.85 x 183.90 mm
Press Sheets Size (w x h): N/A
Plate Size: 120 stamps per revolution
Plate Numbers: “B” followed by six (6) single digits
Marginal Markings:
Front: Plate numbers in four corners of pane
Back: © 2016 USPS • USPS logo • Plate position diagram • Barcode (564200) in upper right and lower left corners of pane • Promotional text

Initial Post on October 3rd:

The U.S. will issue a semi-postal (charity) stamp in November to help fund the fight against Alzheimer’s disease. No date or location was given, nor was the stamp design revealed.

This will be the first of five semi-postal stamps to be issued over the next ten years, with each stamp to be on sale for no more than two years. However, it should be pointed out that the first U.S. semi-postal, for Breast Cancer Awareness (Sc. B1), was also supposed to be on sale for only a limited amount of time, but legislation in Congress has kept it on sale since it was first issued in 1998.

The Alzheimer’s semi-postal will be the sixth issued by the United States, and the first since 2014, when a modified-design version of the first was released. U.S. semipostal stamps are good for first class mail, but currently sell for 60 cents. The additional 11 cents goes to a designated charity.

The U.S. issued an Alzheimer’s Awareness stamp in 2008 as part of its social consciousness program. (Shown above.) However, it was not a semipostal.

Here is the USPS press release:

WASHINGTON — The Semipostal Authorization Act, Pub. L. 106–253, grants the U.S. Postal Service discretionary authority to issue and sell semipostal stamps to advance such causes as it considers to be ‘‘in the national public interest and appropriate.’’ The U.S. Postal Service announced today that in November it will issue the first of five semipostal stamps.

Under the semipostal discretionary program, the Postal Service will issue five stamps over a 10-year period, with each stamp to be sold for no more than two years.

The first stamp issued will be an Alzheimer’s Semipostal Stamp, followed by a Post Traumatic Stress Disorder (PTSD) Semipostal Stamp in 2019. The next three discretionary semipostal stamps have not yet been determined.

The Alzheimer’s Semipostal Stamp will be issued during National Alzheimer’s Awareness Month. Net proceeds will be distributed to the U.S. Department of Health and Human Services. Details on issuance date and location will be provided at a later date.

President Ronald Reagan designated November as National Alzheimer’s Disease Awareness Month in 1983. At the time, fewer than two million Americans were diagnosed with Alzheimer’s; today, that number has soared to nearly 5.4 million.

Semipostal stamps, currently sold for 60-cents, are First-Class Mail (FCM) postage stamps that are issued and sold by the Postal Service at a price above the FCM single-piece one-ounce stamp rate (FCM rate) to raise funds for designated causes.

The difference between the FCM rate in effect at the time of purchase and the 60 cent purchase price, minus an amount to offset costs incurred by the Postal Service, if any, is contributed to the specific cause by law.

Under the Semipostal Authorization Act, the Postal Service will consider proposals for future semipostals until seven years after May 20, 2016. The Federal Register notice outlining this program can be found at the following url: https://www.gpo.gov/fdsys/pkg/FR-2016-04-20/pdf/2016-09081.pdf.

Proposals will only be considered if they meet all submission requirements and selection criteria. They may be submitted by mail to the following address:

Office of Stamp Services
Attn: Semipostal Discretionary Program
475 L’Enfant Plaza SW., Room 3300
Washington, DC 20260–3501

Suggestions may also be submitted in a single Adobe Acrobat (.pdf) file sent by email to semipostal@usps.gov. Indicate in the Subject Line: Semipostal Discretionary Program.

All postage stamps are available for purchase at Post Offices, online at usps.com, and by toll-free phone order at 1-800 STAMP-24.

The Postal Service receives no tax dollars for operating expenses and relies on the sale of postage, products and services to fund its operations.