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Updates from the Advisory Committee on Immunization Practices February Meeting

March 6, 2018 2 comments
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Photo Credit: James Gathany, Centers for Disease Control and Prevention

The Advisory Committee on Immunization Practices (ACIP) held its first meeting of 2018 on February 21st and 22nd.  The Committee consists of a panel of immunization experts that advise the Centers for Disease Control and Prevention (CDC).  Part of their charter is to continually evaluate new data and update or change vaccine recommendations as warranted. 

The agenda for the February 2018 meeting included presentations pertaining to several different diseases and vaccines, to include hepatitis, influenza, anthrax, HPV, pneumococcal, meningococcal and Japanese encephalitis.

A overview of the meeting is provided below, with details on presentations in the order they occurred: 

Hepatitis B

The committee voted unanimously to approve a non-preferential recommendation for a new Hepatitis B vaccine (Dynavax’s HEPISLAV-B™) to their list of recommended vaccines for adults 18 years and older against infections caused by all known subtypes of Hepatitis B.

This vote came following the presentation of data showing that the new two-dose vaccine generates a more rapid and higher antibody response than the standard 3 dose vaccine.

Hepatitis B is a viral disease of the liver that can become chronic and lead to cirrhosis, liver cancer and death. The hepatitis B virus is 50 to 100 times more infectious than HIV, and transmission is on the rise. In 2015, new cases of acute hepatitis B increased by more than 20 percent nationally and 850,000-2.2 million persons are estimated to be living with infection in the U.S.

Since there is no here is no cure for hepatitis B, vaccination is our best chance at preventing the disease. While about 90% of people are infected during infancy, in adults, hepatitis B is most often spread through contact with infected blood and through unprotected sex with an infected person. Some individuals who are especially susceptible include those who are immunosuppressed or living with diabetes. The CDC recommends vaccination for those at high risk for infection due to their jobs, lifestyle, living situations and travel to certain areas.

The Working Group summary suggested that this new vaccine option is likely to improve vaccine series completion and result in earlier protection, which is especially beneficial in persons with anticipated low adherence such as injection drug users.  Additionally, the improved immunogenicity in populations with typically poor vaccine response such as the elderly, diabetics and those on dialysis, is promising.  The ACIP will continue to review post-marketing surveillance studies and additional data to ensure safety and cost-effectiveness considerations.

Hepatitis A

The committee voted unanimously to pass three recommendations pertaining to Hepatitis A.

  • Hepatitis A vaccines should be administered for post-exposure prophylaxis for all persons 12 months of age or older.
  • Hepatitis A vaccine or immune globulin (IG) may be administered to persons 40 years of age or older, depending on the providers’ risk assessment.
  • Hepatitis A vaccine should be administered to infants age 6-11 months of age traveling outside the US when protection against hepatitis A is recommended. This recommendation takes into consideration the fact that infants under 12 months who will be traveling internationally will typically also need an MMR vaccine.  Since Hepatitis A immune globulin and MMR vaccine should not be administered simultaneously, these children should receive a single dose of HepA vaccine. It’s important to note that infants should then complete the full, 2 doses of MMR and HepA vaccines at 12 months of age as recommended.

Influenza

The Committee heard five presentations specific to influenza.

The first two were reports of current season data; one detailing flu surveillance, the other providing early influenza vaccine effectiveness data.

According to the update, the majority of circulating flu strains are similar to those contained in the 2017-2018 vaccine.  The only virus clearly showing antigenic drift was the B/Victoria lineage viruses which represents less than 1% of circulating viruses.  So far this season, influenza A (H3N2) has been dominant, with influenza B activity starting to increase more recently. Activity has been the highest we’ve seen since 2009, and while final severity can’t be determined until the end of the season, hospitalization rates and mortality could be similar to or exceed those send during the severe 2014-2015 season.

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Based on data from 4,562 children and adults with acute respiratory illness enrolled during November 2, 2017–February 3, 2018, at five study sites, the overall estimated effectiveness of the 2017–18 seasonal influenza vaccine for preventing medically attended, laboratory-confirmed influenza virus infection was 36%. The percentage differs by age group and by virus.  A detailed report can be found here.

The most notable news out of the Committee last week was the vote to restore the live attenuated influenza virus (LAIV) vaccine as an option for the 2018-19 season. LAIV is commonly known as the nasal spray flu vaccine or by its brand name, FluMist This renewed ACIP recommendation offers FluMist as one of several vaccine options for non-pregnant people who are 2-49 years of age during the 2018-2019 season, but does not indicate any preference for FluMist over injectable flu vaccines.

While FluMist has not been recommended for the past two flu seasons due to reduced effectiveness against the H1N1 flu strain in children, the Committee heard three presentations specific to LAIV vaccine efficacy in children prior to taking a vote on future recommendations for LAIV.  The first reported on the efficacy of Fluarix Quadrivalent in children 6-35 month of age. Another presented the results of a randomized trial of a new H1N1 LAIV strain in U.S. children. The third was a review LAIV in children 2-17 years of age.  

The possible root cause of the poor effectiveness of LAIV against H1N1 was discussed and poor replication of the H1N1 selected strain was thought to be the likely problem. A new strain selection process is now in place in cooperation with the Food & Drug Administration (FDA) and it suggested that the antibody responses of the latest reformulated version of the quadrivalent vaccine, which includes the new 2017-18 post-pandemic 2009 H1N1 LAIV strain (A/Slovenia), will perform significantly better than what was previously observed when the vaccine included the 2015-16 post-pandemic LAIV strain (A/Bolivia).  Immunogenicity and viral shedding data in small trials supported this notion, but no efficacy data is available at this time.

The Committee was therefore forced to a vote using only the science available to date. There was a lively discussion among members who expressed various concerns. While flu vaccine effectiveness is a serious issue, some committee members expressed concern that they may be holding FluMist to a higher standard than other influenza vaccines, yet all have efficacy challenges from year to year.  Other members were concerned with how the vaccine may perform in an H1N1 dominated season. Until the vaccine is used, further effectiveness assessments are performed, and a prominent H1N1 year occurs, a certain level of uncertainty will remain.

While members voted overwhelmingly (12-2) to reinstate LAIV on the immunization schedule, a second vote to give other flu vaccines a preferential recommendation over LAIV failed (11-3).  So, while the ACIP will not indicate a preference for any one type of flu vaccine over another, the public will ultimately determine whether there will be high uptake of this particular vaccine next season. Read more…

October Updates from Advisory Committee on Immunization Practices

October 26, 2016 3 comments

10693.jpgLast week, the Advisory Committee on Immunization Practices (ACIP) held it’s third and final meeting of 2016.  The agenda included presentations pertaining to hepatitis B, pertussis, HPV, meningococcal, herpes zoster, pneumococcal and RSV vaccines, and surveillance updates on Zika and influenza viruses.

During the two-day meeting, the committee took nine votes on newly proposed vaccine recommendations that addressed vaccination timing, number of doses needed, and dosing intervals for hepatitis B, pertussis, HPV and meningococcal vaccines.  They also approved the child, adolescent and adult immunization schedules.

This post provides a recap of each agenda item in the order they occurred. 

Hepatitis B Vaccine

The recommended first dose of the three-series hepatitis B vaccine is often referred to as “birth dose” and is typically administered to infants in the hospital after birth.  At this meeting, the Hepatitis B Work Group asked that the Committee consider removal of the permissive language that appears at the end of the recommendation which allows for a delay of the birth dose until after hospital discharge.

When hepatitis B vaccine is administered within 24 hours of birth it can help prevent transmission of the hepatitis B virus from an infected mother to her child.  The intent of the birth dose is to provide an additional safety net to prevent transmission from HepB positive mothers that are not properly identified due to errors in maternal testing or reporting. In these instances, when the mother is not properly identified as HepB positive before birth, the HepB vaccine alone is 75% effective in preventing prenatal transmission, and 94% effective when used in conjunction with Hepatitis B immune globulin.

Since delaying hepatitis B vaccination can interfere with the prevention of Hepatitis B – especially in a child unknowingly born to a HepB positive mother – the HepB Work Group proposed that the reference to delaying vaccination be removed from the recommendation.  It had originally been added in 2005, but the data suggests that administering the birth dose in the hospital leads to timely completion of the series. The current birth dose coverage was stated to be 72.4% of children, which remains below the Healthy People 2020 goal of 84%.

The Committee voted to remove the permissive language as well as include new language to clarify that the first dose of vaccine should be administered within 24 hours of birth, which is more explicit than “before hospital discharge”.

The anticipated changes to the previous recommendation are indicated below, however the exact wording may differ once published by the CDC:

“For all medically stable infants weighing 2,000 grams or more at birth and born to HBsAg-negative mothers, the first dose of vaccine should be administered before hospital discharge within 24 hours of birth.  Only single antigen HepB vaccine should be used for the birth dose. On a case-by-case basis and only in rare circumstances, the first dose may be delayed until after hospital discharge for an infant who weighs 2,000 grams or more and whose mother is HBsAG-negative.

*It should be noted that for those infants with birth weight of less than 2,000 grams, the birth dose is not counted as part of the vaccine series.

There was some discussion concerning the removal of the option to delay vaccination and it was emphasized that having a clear recommendation from the ACIP is not a vaccine mandate.  Rather, practitioners, public health professionals and parents rely on the ACIP recommendations as expert guidance and best practice. The Hepatitis B “birth dose” has been a successful strategy to help eliminate hepatitis B virus transmission in the U.S., and the ACIP’s revised recommendations only emphasize the importance of vaccinating within the 24 hours timeframe that will help prevent further transmission.

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Other key updates to the hepatitis B vaccine recommendations included:

  • Providing examples of chronic liver disease, including recommending HepB vaccine for persons with HCV infection.
  • Post vaccination serologic testing for infants who’s mother’s HBsAg status remains  unknown indefinitely.
  • Testing HBsAg-positive pregnant women for HBV DNA.

For more information as to why babies need a Hepatitis B vaccine at birth, read these Shot of Prevention blog posts here

Pertussis Vaccine

The Committee reviewed the history of Tdap vaccination in pregnant women and reviewed studies that found that maternal Tdap vaccination to both safe and effective at preventing infant pertussis. Read more…