Like many of us, you may have questions about the Pfizer and Moderna vaccines.

Here are the latest answers from state and US health officials.

Can I wait longer than 2 - 3 weeks between doses?

Last week, health officials decided it was OK to delay the 2nd dose as long as 12 weeks.

The 1st shot will provide you with at least some protection, according to unpublished data from the AstraZeneca vaccine trial. 

But on Monday, the U.S. Food and Drug Administration said far too few people in both the Pfizer and Moderna vaccine studies missed an on-time booster shot to have enough data to show the strategy might work.

Could supply be stretched by using smaller doses? 

Dr. Moncef Slaoui, who advises the vaccine program Operation Warp Speed, said some data shows 2 half-doses of the Moderna vaccine might work.

But the FDA late Monday dismissed that dose-stretching idea and said that just like the postponed boosters theory.

Trying such strategies without data to support them could backfire, undermining vaccination efforts to protect all of us.

Would stretching doses speed up vaccinations?

It’s far from clear that stretching doses will get them into people’s arms any faster.

In SC and the US, initial doses haven’t been used nearly as fast as experts had hoped.

As of this week, more than 4.5 million people have been vaccinated out of more than 15 million doses the government has shipped to the states.

Can my 2nd dose be a different vaccine than my first?

Don’t mix and match, says the FDA. There’s no data showing if vaccines can be interchanged.

In fact, that’s why the government is holding millions of vaccine doses in reserve, until it’s clear that getting more supplies in time for everyone’s booster isn’t a problem.

When you are vaccinated, you will get a card with information about which vaccine you received and when to return for the 2nd dose.