Mehmet Oz, M.D., is host of “The Dr. Oz Show,” and Mike Roizen, M.D., is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. Email questions to youdocsdaily@sharecare.com.

QUESTION: I heard that the flu vaccine worked only 20 to 25 percent of the time last year. Is it even worth getting it this year?

— Lolly G., Stamford, Conn.

ANSWER: It’s always worth getting the flu shot, and that 20 to 25 percent effectiveness number was simply an early estimate.

The Centers for Disease Control and Prevention states the effectiveness rate ended up around 36 percent across several different flu strains, but primarily guarded against H3N2.

However, even a 20 percent effectiveness rate — as was the case in 2014-15 — prevents an estimated 144,000 flu-related hospitalizations and 4,000 deaths. This year, the vaccine almost doubled that prevention/death rate. That’s avoiding a lot of misery.

So, yes, get your flu shot as soon as it’s available this fall.

Don’t forget, there’s also a cumulative benefit.

We can’t put an exact number on it, but we do know that people who receive the vaccination year after year, and who still end up getting sick, tend to have less severe symptoms for a shorter period of time than unvaccinated folks. And getting the flu shot 10 years in a row from age 50 to 60 decreases all causes of death, including from stroke and heart attack, by more than 25 percent.

So protect yourself and your family by getting vaccinated when the time is right; there’s a schedule for all of your vaccinations at cdc.gov/vaccines/schedules.

Q: Should I take vitamin D while I’m pregnant? Should I give a supplement to my 2-year-old?

— Claudia H., Mill Valley, Calif.

A: Vitamin D deficiency is common in pregnant women, and if you have low levels, that translates to low vitamin D levels in your fetus and your newborn. Research shows the deficiency may interfere with fetal development of bones, lungs and the immune system, and lead to a newborn with reduced growth and a greater chance of respiratory problems.

According to the American College of Obstetricians and Gynecologists, women who are vegetarians, have limited sun exposure and are members of ethnic minorities, especially those with darker skin, are at greatest risk for vitamin D deficiency.

As for whether you should take supplements or supplement your toddler, there are two studies in the JAMA journal Pediatrics that suggest benefits of supplements -— but talk with your obstetrician and your toddler’s pediatrician before you decide what to do.