--- description: Flu season 2018 may see a second wave, as influenza B viruses have overtaken influenza A viruses. It's not too late to get a flu shot. title: A Second Wave Of Flu May Be On the Way, CDC Warns image: https://static.time.com/v3/assets/bltea6093859af6183b/bltbd60681427407eb2/69892c1486f68ea4e96e8b55/flu-shot.jpeg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 ---  * [Health](/section/health/) ## Health Update your preferences in [Account Settings](/account/preferences/) Close * [Public Health](/tag/public-health/) ## Public Health Update your preferences in [Account Settings](/account/preferences/) Close # A Second Wave of Flu May Be On the Way, CDC Warns  by [Jamie Ducharme](/author/jamie-ducharme/)  ## Jamie Ducharme Update your preferences in [Account Settings](/account/preferences/) Close Ducharme is a contributor to TIME. Mar 27, 2018 3:33 PM CUT  A nurse administers a flu shot. A nurse administers a flu shot.Bloomberg—Bloomberg via Getty Images  by [Jamie Ducharme](/author/jamie-ducharme/)  ## Jamie Ducharme Update your preferences in [Account Settings](/account/preferences/) Close Ducharme is a contributor to TIME. Mar 27, 2018 3:33 PM CUT Flu season [may have peaked in February](http://time.com/5183507/flu-season-peaked/ "undefined"), but we’re not out of the woods yet. The bulk of [this year’s deadly flu season](http://time.com/5108077/2018-flu-map/ "undefined") was dominated by the H3N2 virus, an influenza A strain that is more severe and less receptive to vaccines than other types of the disease. As the season winds down, however, influenza B has overtaken influenza A, setting the scene for a possible second wave of flu, [according to Centers for Disease Control and Prevention](https://www.cdc.gov/flu/weekly/ "undefined") (CDC) data. While flu activity nationwide has dropped to just above non-flu-season levels, influenza B viruses were reported more frequently than influenza A viruses during the week ending March 17, according to the CDC. Influenza B infections, which commonly strike later in the season, may be especially severe for young children, [a CDC spokesperson told CNN](https://www.cnn.com/2018/03/23/health/flu-surveillance-weekly-march-23-cdc/index.html "undefined"). Even those who already got the flu this year may not be safe, since [it’s possible to get sick with both](http://www.health.com/cold-flu-sinus/can-you-get-flu-twice-in-one-season "undefined") influenza A and influenza B in a single season. The good news, however, is that influenza B viruses traditionally respond better to vaccines than influenza A viruses. By [CDC estimates](http://time.com/5160213/flu-shot-effectiveness-2018/ "undefined"), this year’s flu shot was 42% effective against influenza B, versus 25% effective against H3N2. And believe it or not, it’s still not too late to get a shot if you haven’t. The CDC [recommends vaccination](https://www.cdc.gov/flu/weekly/summary.htm "undefined") “as long as flu viruses are circulating” — and with 17 states still reporting widespread flu activity, that puts us squarely within that window. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/5216990/influenza-b-flu-season-2018/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/5216990/influenza-b-flu-season-2018/"},"headline":"A Second Wave of Flu May Be On the Way, CDC Warns","datePublished":"2018-03-27T15:33:45.000Z","dateModified":"2026-02-23T19:47:19.246Z","description":"Even if you've already had the flu, you could get sick again","url":"https://time.com/5216990/influenza-b-flu-season-2018/","keywords":["Public Health","onetime","healthytime"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/bltbd60681427407eb2/69892c1486f68ea4e96e8b55/flu-shot.jpeg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Jamie Ducharme","jobTitle":"Ducharme is a contributor to TIME.","url":"https://time.com/author/jamie-ducharme/"}],"articleSection":"Health","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/bltbd60681427407eb2/69892c1486f68ea4e96e8b55/flu-shot.jpeg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"Inside Perry Memorial Hospital As Senators Get Deal To Prop Up Obamacare","caption":"Inside Perry Memorial Hospital As Senators Get Deal To Prop Up Obamacare","creditText":"Bloomberg—Bloomberg via Getty Images","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/health/","name":"Health"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/public-health/","name":"Public Health"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/5216990/influenza-b-flu-season-2018/","name":"A Second Wave of Flu May Be On the Way, CDC Warns"}}]}] ```