{"id":102,"date":"2024-07-22T18:52:35","date_gmt":"2024-07-22T18:52:35","guid":{"rendered":"https:\/\/www.merckvaccines.com\/proquad\/?page_id=102"},"modified":"2026-03-31T08:58:56","modified_gmt":"2026-03-31T08:58:56","slug":"febrile-seizures","status":"publish","type":"page","link":"https:\/\/www.merckvaccines.com\/proquad\/febrile-seizures\/","title":{"rendered":"Febrile seizures"},"content":{"rendered":"<link rel='stylesheet' id='vivid360-spacer-css-css' href='https:\/\/www.merckvaccines.com\/proquad\/wp-content\/themes\/cex-wpvip-mhh-merck-vivid360-theme-1-12\/blocks\/spacer\/css\/style.min.css?ver=1766071753' media='all' \/>\n\n<div style=\"background-color:transparent;--desktop-spacer:0px;--tablet-spacer:16px;--mobile-spacer:16px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n<link rel='stylesheet' id='vivid360-hero-css-css' href='https:\/\/www.merckvaccines.com\/proquad\/wp-content\/themes\/cex-wpvip-mhh-merck-vivid360-theme-1-12\/blocks\/hero\/css\/style.min.css?ver=1766071753' media='all' \/>\n\n<div id=\"\" class=\"wp-block-vivid360-hero\"><div class=\"vivid360-hero-container align-left align-middle ratio-70-30 horizontal desktop text-align-left has-primary-dark-color is-overlay-style is-card-overlay is-opaque-overlay mobile-is-default-style mobile-uses-custom-styles\" style=\"border-width:0;border-style:solid;border-top-left-radius:0;border-top-right-radius:0;border-bottom-right-radius:0;border-bottom-left-radius:0;--minHeight:218px;--mobileMinHeight:162px\"><div class=\"wide_screens hidden\" data-value=\"default\"><\/div><picture><source media=\"(max-width: 767px)\" srcset=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/4.0_Clinical_Data_ProQuad_Banner_1128px_v2.svg?w=767\"\/><source media=\"(min-width: 768px) and (max-width:1024px)\" srcset=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/4.0_Clinical_Data_ProQuad_Banner_1128px_v2.svg?w=1024\"\/><source media=\"(min-width: 1025px) and (max-width:1440px)\" srcset=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/4.0_Clinical_Data_ProQuad_Banner_1128px_v2.svg?w=1440\"\/><img decoding=\"async\" width=\"1128\" height=\"242.58\" loading=\"lazy\" data-src=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/4.0_Clinical_Data_ProQuad_Banner_1128px_v2.svg?w=1488\" src=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/4.0_Clinical_Data_ProQuad_Banner_1128px_v2.svg?w=1488\" alt=\"\" class=\"hero-image\" style=\"--desktop-focal-x:94%;--desktop-focal-y:38%;--mobile-focal-x:12%;--mobile-focal-y:49%;--tablet-focal-x:94%;--tablet-focal-y:38%\"\/><div class=\"capoverlay-container-desktop right-bottom show custom_margin hide_mobile isMobileOverlayChecked label\" style=\"--top-margin:;--bottom-margin:;--left-margin:;--right-margin:8px\"><div class=\"overlay-caption-schema\">Actor Portrayal<\/div><\/div><\/picture><div class=\"hero-wrapper\"><div class=\"hero-content\"><h1 style=\"--headlineFontSize:30px;--headlineFontSizeTablet:36px;--headlineFontSizeMobile:22px;--headlineLineHeight:45px;--headlineLineHeightTablet:45px;--headlineLineHeightMobile:33px\" class=\"hero-title fontWeightRegular\"><strong>ProQuad\u00ae (Measles, Mumps, Rubella and Varicella Virus Vaccine Live) as the 2nd MMRV Dose: Clinical data on febrile seizures<\/strong><\/h1><p class=\"hero-description\"><\/p><div class=\"hero-btn-group\"><\/div><div class=\"hero-caption\"><\/div><\/div><\/div><\/div><div class=\"hero-caption-2desktop\"><\/div><\/div>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:20px;--tablet-spacer:24px;--mobile-spacer:24px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<p>Get the facts about the risk of febrile seizures after the second dose of ProQuad\u00ae (Measles, Mumps, Rubella and Varicella Virus Vaccine Live)<\/p>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:12px;--tablet-spacer:8px;--mobile-spacer:8px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<div class=\"wp-block-columns are-vertically-aligned-top is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-vertically-aligned-top hasBoxShadow padding-left-right15 is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:50%\">\n<div style=\"background-color:transparent;height:16px\" class=\"wp-block-vivid360-spacer vivid360-spacer spacer-16\"><\/div>\n\n\n<link rel='stylesheet' id='vivid360-image-css-css' href='https:\/\/www.merckvaccines.com\/proquad\/wp-content\/themes\/cex-wpvip-mhh-merck-vivid360-theme-1-12\/blocks\/image\/css\/style.min.css?ver=1766071753' media='all' \/>\n\n<div class=\"wp-block-vivid360-image img-container ml-0 mr-0 mt-0 mb-0\"><figure class=\"wp-block-vivid360-image is-style-default has-mobile-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2026\/03\/merck-preprod.go-vip.co_proquad-mv_febrile-seizures_Desktop-1440x1024-1.png\" alt=\"\" class=\"wp-image-1894  style-noshadow deskHeightAuto deskWidthAuto \" style=\"height:576px;width:1024px\" srcset=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2026\/03\/merck-preprod.go-vip.co_proquad-mv_febrile-seizures_Desktop-1440x1024-1.png 1024w, https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2026\/03\/merck-preprod.go-vip.co_proquad-mv_febrile-seizures_Desktop-1440x1024-1.png?resize=300,169 300w, https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2026\/03\/merck-preprod.go-vip.co_proquad-mv_febrile-seizures_Desktop-1440x1024-1.png?resize=768,432 768w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2026\/03\/merck-preprod.go-vip.co_proquad-mv_febrile-seizure-data-video_New-Mobile.png\" alt=\"\" class=\"wp-image-1895  style-noshadow mobile-image mobHeightAuto mobWidthAuto \" width=\"716\" height=\"404\" title=\"\" style=\"height:404px;width:716px\" srcset=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2026\/03\/merck-preprod.go-vip.co_proquad-mv_febrile-seizure-data-video_New-Mobile.png 716w, https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2026\/03\/merck-preprod.go-vip.co_proquad-mv_febrile-seizure-data-video_New-Mobile.png?resize=300,169 300w\" sizes=\"auto, (max-width: 716px) 100vw, 716px\" \/><\/figure><\/div>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:12px;--tablet-spacer:6px;--mobile-spacer:16px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n<link rel='stylesheet' id='vivid360-heading-css-css' href='https:\/\/www.merckvaccines.com\/proquad\/wp-content\/themes\/cex-wpvip-mhh-merck-vivid360-theme-1-12\/blocks\/heading\/css\/style.min.css?ver=1766071753' media='all' \/>\n\n<div class=\"vivid360-heading default-hcp-fontsize default-hcp-tablet-fontsize default-hcp-mobile-fontsize\" id=\"a2ea0dd0d-2d7e-40d8-a4ae-81f6a32acc3c\"><h2 class=\"content-width fontWeightRegular\" style=\"--desktopFontSize:var(--h2FontSizeDesktop);--tabletFontSize:var(--h2FontSizeDesktop);--mobileFontSize:var(--h2FontSizeMobile);--desktopLineHeightSize:var(--h2LineHeightDesktop);--tabletLineHeightSize:var(--h2LineHeightDesktop);--mobileLineHeightSize:\" id=\"\"><strong>MMRV series completion with ProQuad<\/strong><\/h2><\/div>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:2px;--tablet-spacer:10px;--mobile-spacer:10px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<p>Since 2010, the Advisory Committee on Immunization Practices generally preferred combination MMRV for second dose vaccination against measles, mumps, rubella, and varicella.<\/p>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:10px;--tablet-spacer:8px;--mobile-spacer:8px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<p><span class=\"\"><a href=\"\/proquad\/febrile-seizure-data-video\/\" aria-label=\"#\">Watch video<\/a><\/span><\/p>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:30px;--tablet-spacer:24px;--mobile-spacer:24px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n<\/div>\n<\/div>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:22px;--tablet-spacer:24px;--mobile-spacer:24px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<p class=\"has-primary-dark-color has-text-color\"><strong>Incidence of febrile seizure with ProQuad vs <span class=\"no-wrap-text\">M-M-R<sup>\u00ae<\/sup><sub>II<\/sub><\/span> (Measles, Mumps, and Rubella Virus Vaccine Live) + VARIVAX<sup>\u00ae<\/sup> (Varicella Virus Vaccine Live) per 1000 children 12 months to 60 months of age.<\/strong><\/p>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:22px;--tablet-spacer:16px;--mobile-spacer:16px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<div class=\"wp-block-vivid360-image\"><div class=\"img-container mb-0 mt-0\"><figure class=\"wp-block-vivid360-image is-style-default has-mobile-image aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/ProQuad-Febrile-Seizures-Safety-Data-CHART_ARIAL_v4@4x.png?w=1022\" alt=\"Incidence of Febrile Seizure 5-12 Days and 0-30 Days After 1st Dose of ProQuad\u00ae (Measles, Mumps, Rubella and Varicella Virus Vaccine Live) Versus M-M-R\u00aeII (Measles, Mumps, and Rubella Virus Vaccine Live) and VARIVAX\u00ae (Varicella Virus Vaccine Live) and Incidence of Febrile Seizure 5-12 Days After 2nd Dose of ProQuad\u00ae\" class=\"wp-image-1840  style-noshadow deskHeightAuto  \" width=\"767\" height=\"198\" style=\"height:198px;width:767px\" srcset=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/ProQuad-Febrile-Seizures-Safety-Data-CHART_ARIAL_v4@4x.png 1022w, https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/ProQuad-Febrile-Seizures-Safety-Data-CHART_ARIAL_v4@4x.png?resize=300,77 300w, https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/ProQuad-Febrile-Seizures-Safety-Data-CHART_ARIAL_v4@4x.png?resize=768,198 768w\" sizes=\"auto, (max-width: 767px) 100vw, 767px\" \/><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/ProQuad-Febrile-Seizures-Safety-Data-CHART_STACKED_ALL2@4x.svg\" alt=\"Incidence of Febrile Seizure 5-12 Days and 0-30 Days After 1st Dose of ProQuad\u00ae (Measles, Mumps, Rubella and Varicella Virus Vaccine Live) Versus M-M-R\u00aeII (Measles, Mumps, and Rubella Virus Vaccine Live) and VARIVAX\u00ae (Varicella Virus Vaccine Live) and Incidence of Febrile Seizure 5-12 Days After 2nd Dose of ProQuad\u00ae\" class=\"wp-image-1841  style-noshadow mobile-image  mobWidthAuto \" width=\"231\" height=\"673\" title=\"\" style=\"height:673px;width:231px\" srcset=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/\/2025\/12\/ProQuad-Febrile-Seizures-Safety-Data-CHART_STACKED_ALL2@4x.svg 617w, https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/\/2025\/12\/ProQuad-Febrile-Seizures-Safety-Data-CHART_STACKED_ALL2@4x.svg?resize=103,300 103w, https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/\/2025\/12\/ProQuad-Febrile-Seizures-Safety-Data-CHART_STACKED_ALL2@4x.svg?resize=352,1024 352w, https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/\/2025\/12\/ProQuad-Febrile-Seizures-Safety-Data-CHART_STACKED_ALL2@4x.svg?resize=528,1536 528w\" sizes=\"auto, (max-width: 231px) 100vw, 231px\" \/><\/figure><\/div><\/div>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:22px;--tablet-spacer:0px;--mobile-spacer:0px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:30px;--tablet-spacer:24px;--mobile-spacer:24px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<p>Administration of ProQuad (dose 1) to children 12 to 23 months old who have not been previously vaccinated against measles, mumps, rubella, or varicella, nor had a history of the wild-type infections, is associated with higher rates of fever and febrile seizures at 5 to 12 days after vaccination when compared to children vaccinated with dose 1 of both <span class=\"no-wrap-text\">M-M-R<sup>\u00ae<\/sup><sub>II<\/sub><\/span> and VARIVAX administered concomitantly.<\/p>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:30px;--tablet-spacer:24px;--mobile-spacer:24px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:30px;--tablet-spacer:24px;--mobile-spacer:24px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<div class=\"vivid360-heading default-hcp-fontsize default-hcp-tablet-fontsize default-hcp-mobile-fontsize\" id=\"a09b32935-d2c9-4ed1-b953-993cc99416fd\"><h2 class=\"content-width fontWeightRegular\" style=\"--desktopFontSize:var(--h2FontSizeDesktop);--tabletFontSize:var(--h2FontSizeDesktop);--mobileFontSize:var(--h2FontSizeMobile);--desktopLineHeightSize:var(--h2LineHeightDesktop);--tabletLineHeightSize:var(--h2LineHeightDesktop);--mobileLineHeightSize:\" id=\"\"><strong>Study design<\/strong><\/h2><\/div>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:20px;--tablet-spacer:24px;--mobile-spacer:24px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<p>Safety was evaluated in an observational study that included 69,237 children aged 12 months to 12 years vaccinated with ProQuad after a 1st dose with <span class=\"no-wrap-text\">M-M-R<sup>\u00ae<\/sup><sub>II<\/sub><\/span> + VARIVAX. A historical comparison group included 69,237 age-, gender-, and date-of-vaccination (day and month) matched subjects who were given <span class=\"no-wrap-text\">M-M-R<sup>\u00ae<\/sup><sub>II<\/sub><\/span> and VARIVAX concomitantly. The primary objective was to assess the incidence of febrile seizures occurring within various time intervals after vaccination in 12- to 60-month-old children who had neither been vaccinated against measles, mumps, rubella, or varicella, nor had a history of the wild-type infections (N=31,298 vaccinated with ProQuad, including 31,043 who were 12 to 23 months old). The incidence of febrile seizures was also assessed in a historical control group of children who had received their first vaccination with M-M-R<sup>\u00ae<\/sup><sub>II<\/sub> and VARIVAX concomitantly (N=31,298, including 31,019 who were 12 to 23 months old). The secondary objective was to assess the general safety of ProQuad in the 30-day period after vaccination in children 12 months to 12 years old.<\/p>\n\n\n\n<div style=\"background-color:transparent;--desktop-spacer:22px;--tablet-spacer:18px;--mobile-spacer:18px\" class=\"wp-block-vivid360-spacer vivid360-spacer-desktop vivid360-spacer-tablet vivid360-spacer-mobile\"><\/div>\n\n\n\n<p><\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><link rel='stylesheet' id='vivid360-card-css-css' href='https:\/\/www.merckvaccines.com\/proquad\/wp-content\/themes\/cex-wpvip-mhh-merck-vivid360-theme-1-12\/blocks\/card\/css\/style.min.css?ver=1773241827' media='all' \/>\n\n<div id=\"\" class=\"wp-block-vivid360-card afeb671f6-dbf1-4ea2-90b4-a8d7f5ff9cc0 vivid360-block-card has-text-align-left hasBoxShadow card-horizontal has-primary-color full-page-width\" style=\"border-width:0px;border-style:;border-radius:0\"><div class=\"card-media \"><figure class=\"ratio-1-1\"><picture><source media=\"(max-width: 767px)\" data-srcset=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/Icon-3-8.png?w=767\"\/><source media=\"(min-width: 768px) and (max-width: 1440px)\" data-srcset=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/ProQuad_CDC_Recommendations_Icon_KO.svg?w=1440\"\/><img decoding=\"async\" width=\"68\" height=\"200\" data-src=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/ProQuad_CDC_Recommendations_Icon_KO.svg\" loading=\"lazy\" src=\"https:\/\/www.merckvaccines.com\/proquad\/wp-content\/uploads\/sites\/174\/2025\/12\/ProQuad_CDC_Recommendations_Icon_KO.svg\" alt=\"\"\/><\/picture><\/figure><\/div><div class=\"card-content\"><div class=\"card-content-wrap\"><h2 class=\"card-header fontWeightRegular\"><strong>See CDC recommendations<\/strong><\/h2><p class=\"card-link entire-card left\"><a class=\"\" href=\"\/proquad\/\" role=\"button\" style=\"border-radius:4px\" title=\"See CDC recommendations\" target=\"_self\" rel=\"noopener\" data-design-category=\"link\" data-design-label=\"See CDC recommendations\" data-design-module=\"element\">See CDC recommendations<\/a><\/p><\/div><div class=\"\"><div class=\"card-icon-right\"><i role=\"link\" aria-label=\"\" aria-hidden=\"true\" class=\"icon-arrow-right\"><\/i><\/div><\/div><\/div><\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Get the facts about the risk of febrile seizures after the second dose of ProQuad\u00ae (Measles, Mumps, Rubella and Varicella Virus Vaccine&#8230;<\/p>\n","protected":false},"author":522,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"_trash_the_other_posts":false,"editor_notices":[],"footnotes":""},"ga4_page_audience":[],"ga4_page_birn_id":[],"ga4_page_branding":[228],"ga4_page_businessunit":[239],"ga4_page_campaign":[],"ga4_page_content_purpose":[262,1066,1067],"ga4_page_customer_journey_stage":[319],"ga4_page_customer_specialty":[375],"ga4_page_experience":[],"ga4_page_indication":[484],"ga4_page_material_intent":[582],"ga4_page_product":[762],"ga4_page_region":[934],"ga4_page_therapeuticarea":[951],"class_list":["post-102","page","type-page","status-publish"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.7 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Incidence of Febrile Seizures After 2nd MMRV Vaccine Dose<\/title>\n<meta name=\"description\" content=\"Review the incidence of 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