HALF THE DOSE GIVEN FOR THE BOOSTER DOSE; OFF LABEL USE; This spontaneous report received from a health care professional concerned a 59 year old female of an unspecified race and ethnic origin. The patient's height, and weight were not reported. No past medical history or concurrent conditions were reported. The patient received covid-19 vaccine ad26.cov2.s (unspecified manufacturer) (dose number in series 1) (suspension for injection, route of admin not reported, batch number: unknown, expiry: unknown) dose was not reported, 1 total, administered on unspecified date for prophylactic vaccination. No adverse event was reported (dose number in series 1).  The patient received covid-19 vaccine ad26.cov2.s (dose number in series 2) (suspension for injection, route of admin not reported, lot number was reported as 211A21A (additional lot number was reported as 1822809) and expiry: UNKNOWN) dose was not reported, 1 total, administered on 26-NOV-2021 for prophylactic vaccination. No concomitant medications were reported. On 26-NOV-2021, half the dose [was] give for the booster dose and off label use occurred (dose number in dose series 2). HCP (health care professional) (from public health dept) described that there were 33 patients who received half doses (0.25ml (milliliter)) for their booster or 3rd dose a few days ago. Most of them were patients from state. HCP stated that something was printed and disseminated that said to administer .25ml. HCP was not sure where that information came from. Stated it was over the holidays so people could have thought that info changed and staff was just not made aware. HCP did not think it had been reported yet through VAERS. HCP thought that the vendor will file the report with VAERS, not public health department. HCP stated that they figured it out after the event because they could not figure out how so many doses were given. They were looking for a discrepancy in the number of vials perhaps, but then realized that half doses were given. HCP consented to being contacted, but stated that she may not be the best person to contact. If she had an alternate contact she would provide it to whomever reached out to her. The reporter went on to report that HCP stated that (PRIVATE) is the vendor. At the time of the discussion they were both teaming up together to gather information and they may have called to report these events as well, so HCP warned to be mindful of possible duplicate reports. The action taken with covid-19 vaccine ad26.cov2.s (dose number in series 2) was not applicable  The outcome of received half doses 0.25ml for their booster and off label use was not reported. This report was non-serious. This case, from the same reporter is linked to 20211202250, 20211201046, 20211202193, 20211201228, 20211201168, 20211200752, 20211201351, 20211200994, 20211201450, 20211204104, 20211201179, 20211201443, 20211220146, 20211220262, 20211220250, 20211220145, 20211220619, 20211220129, 20211219871, 20211219926, 20211202379, 20211202515, 20211202371, 20211202246, 20211202207, 20211202199, 20211202161, 20211201392, 20211201362, 20211201304, 20211201082, 20211200769, 20211200723, 20211200675, 20211200717 and 20211165041.