Tag: calendar

How Long Is a Vaccine Month?

Are you ever concerned that your kids will get their vaccines too early or too late?

Vaccine intervals are typically based on weeks and "months."
Vaccine intervals are typically based on weeks and “months.” But how long is a month?

For example, if your child needs a booster dose of a vaccine in a month, just how long is that?

Does it depend on which month you are in?

For intervals of 3 months or less, you should use 28 days (4 weeks) as a “month.”

Ask the Experts on Scheduling Vaccines

In general, while we often use calendar months, because it is more convenient, you can use a minimum interval of 28 days or 4 weeks as a full month, as long as we are only counting up to three months.

So a second flu shot after a dose on January 1st could be done as early as January 29th. That’s technically one month (28 days, 4 weeks) later. And no, you wouldn’t have to repeat the second dose if you got it on February 1st, as we are typically worried about the minimum intervals or spacing and not about getting the dose a little late.

For intervals of 4 months or longer, you should consider a month a “calendar month”: the interval from one calendar date to the next a month later.

Ask the Experts on Scheduling Vaccines

And just count calendar months if you are counting more than 3 months. So if you got a vaccine on January 1 and needed another 4 months later, you would return on May 1.

Why switch to using “calendar months” for longer intervals? With longer 28 day intervals, scheduling mistakes will likely be made.

More on Spacing and Scheduling Vaccine Doses