LAS VEGAS (KLAS) — Health officials do not want COVID-19 vaccine doses to go to waste, so they are encouraging Nevadans who have scheduled multiple appointments to cancel their duplicates.

It is possible that some doses cannot be used, if the end of the day approaches at distribution sites. That is because of their scientific properties.

“When you have extra, it’s really an ethical question: what do you do?” said Dr. Marc J. Kahn, Dean of the UNLV School of Medicine.

Dr. Marc J. Kahn — Dean of the UNLV School of Medicine

But the answer to that question is not that simple.

The Pfizer and Moderna COVID-19 vaccines both require cold storage. Dr. Kahn says before the vaccine can be administered, it is diluted with water. But that happens per vial, so all of it must be used.

“We don’t take the vial out, dilute it, and then put it back,” Dr. Kahn said. “Once it’s out of minus 80, it’s out of minus 80.”

The doses are put into syringes for distribution, but they have a limited shelf life.

“You have to actually give those vaccines within a period of time, or you have to discard them,” Dr. Kahn said.

Some Nevadans have been able to get a shot before they are eligible, just by showing up at vaccination sites. But the Southern Nevada Health District (SNHD) says that is rare.

“We try not to waste any vaccine at all, so some of those people have had success with that,” said Greg Cassell, with SNHD’s Incident Management Team. “But our pharmacy teams are getting very good at estimating what they exactly need to close out the day, so there’s not very many, if any, of those at the end of the day.”

Greg Cassell—SNHD’s Incident Management Team

State leaders said they would look into consequences for those jumping the line. 8 News Now asked Cassell if the health district has received any guidance from the State on how to handle those situations. He says they have not.

If the goal is to protect all Nevadans, Dr. Kahn says: “We need to use all the vaccine that we have.”

Dr. Kahn says one thing to look forward to is Johnson & Johnson’s COVID-19 vaccine, which he expects the FDA will soon approve for emergency use authorization. That vaccine does not require ultra-cold storage.