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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…

Is This Season’s Flu More Severe Than Usual or Just Highly Active?

January 13, 2018 10 comments

At this point in the flu season people often wonder if all the media hype is part of an orchestrated effort to panic people about flu, or if it is really signaling serious concern.

There are lots of flu stories in the news these days.  From reports of  74 Californian’s who’ve died from flu – five times the number seen at this point last year – to 13 school districts in TX closing due to the high number of flu cases among students, we’re left to wonder….

Is this year’s flu season more severe than usual or just highly active at the moment?

A recent CDC media briefing has helped clarify the following concerns regarding the latest flu activity in the U.S.: 

Right now, flu is widespread everywhere.  

One of the most notable differences between this season and others is in relation to the geographic spread of flu. This is the first time over the course of 13 years of surveillance data that the entire nation is experiencing widespread flu at the exact same time, as can be noted by the color of CDC’s flu surveillance map below.

FluWeeklyReportActivity is severe right now.

 

One of the ways the CDC tracks influenza activity is to record the number of lab confirmed cases of flu and hospitalizations by week. What they’ve noted is a very rapid increase in the number of people seeing their healthcare providers for flu diagnosis, along with a rapid rise in the numbers of people being hospitalized with lab confirmed flu. For instance, this week’s surveillance data indicates that there’s been 22.7 hospitalizations per 100,000 people in the U.S., which is up considerably from the 13.7 number recorded last week.

So far this season, influenza A (H3N2), has been the most prevalent strain in circulation. Unfortunately, historically it is often the strain linked to more severe illness, especially among children and older individuals above the age of 65. Interestingly enough, the current flu surveillance observations seem to be in line with two more previous H3N2 dominant seasons; the 2014-2015 and 2012-2013 seasons.WHOPHL02_small

Additionally the hospitalizations so far this season seem to be in line with other H3N2 predominant seasons, with the highest rates among those over the age of 65, those between 50-64, and children under 5 years of age.

Flu can cause mild disease in some, but severe disease and death in others.

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Sadly, there have been as many as 30 pediatric deaths so far this season. While children are at great risk, there are plenty of reports of otherwise healthy adults who have been hospitalized or died from flu this season.

Peak season may have started early, but there are many more weeks to go.

Speaking to the media on behalf of the CDC on Friday, Dr.  Jernigan explained,

“If we look at the timing of the season, even if we have hit the top of the curve or the peak of the seasonal activity, it still means we have a lot more flu to go.”

He went on to suggest that there will likely be at least 11 to 13 more weeks of elevated influenza activity this season, before activity begins to subside. Even though it can take about two weeks for protection from vaccination to set in, Dr. Jernigan explained that we still have a lot of flu season to get through and that vaccination efforts should continue as long as influenza viruses are circulating.

While we are seeing a lot of H3N2 circulating now, we are also seeing H1N1 show up in states that have already had H3N2 activity. And we know that B viruses also tend to show up later in the season. Each of these strains are covered in the vaccine, so flu vaccination now can still help to prevent, or lessen the severity of flu throughout the remainder of the season.

Vaccination is our best defense.  

While flu vaccination is far from perfect, it remains our best defense. Not only can it help prevent flu, but it can also help lessen the severity of symptoms if a vaccinated person does end up getting infected.  This can reduce the chances of an individual being hospitalized or dying from flu.

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In fact, a recent study showed that influenza vaccination reduced the risk of flu-associated death by 65% among healthy children and by 51% among children with underlying high-risk medical conditions. Another study indicated that many older adults benefit from repeated flu vaccination. When getting vaccinated in both the current and previous seasons, the study found flu vaccination was 74% effective in preventing ICU admissions in older individuals and 70% effective in preventing deaths among older adults.

Manufacturers are reporting that they’ve shipped more than 151 million doses of flu vaccine this season, so there shouldn’t be a problem finding a flu vaccine in your area.  Simply refer to the flu vaccine finder for assistance.

We won’t know preliminary flu vaccine effectiveness until February.  

Read more…

The 60/40 Factor and This Year’s Flu Season: It’s Not Over Yet

March 10, 2017 4 comments

It’s March, and while we may be anxious for the arrival of spring, what we’ve seen instead is a whole lot of people sick with flu.  Surveillance data shows that while the flu may have peaked in some areas of the country, flu activity remains elevated throughout most of the U.S.  Since flu season typically extends into April and May, now is the time to remain vigilant and get vaccinated if that is still something you haven’t managed to do.

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Flu surveillance reports indicate that the flu strains that make up this year’s vaccine are a good match to those circulating across the U.S.  The most dominant strain has been the influenza A (H3N2) strain, and the estimated effectiveness of the vaccine in preventing illness caused by that strain has been 43%. However, we’re also seeing cases of influenza B virus, and the vaccine’s estimated effectiveness against that strain is 73%. This amounts to an overall vaccine protection of about 48%.

While some may question, “Why get a flu shot if it doesn’t guarantee you won’t get the flu?”, the answer is simple. 48% protection is much better than none.

When a vaccinated individual is exposed to flu, they are about half as likely to have to go to the doctor, be hospitalized or even die from the flu as compared to their unvaccinated counterpart.

Sure, the flu vaccine isn’t perfect.  But that doesn’t mean it’s not worth getting.  

Consider the fact that most everyone wears a seat belt when driving in a car, and yet they’ve only been shown to reduce vehicular injury and death by about 50%.  So if you wouldn’t drive your car without wearing a seatbelt, why would you want to skip a flu shot?

Another reason people often use to explain why they haven’t gotten a flu vaccine is because they’ve never had the flu and they don’t consider it to be dangerous.

The 60/40 factor tells us otherwise.

40:  This is the number of children who’ve died from the flu so far this season.  

While no parent every imagines that their child will die from a preventable disease, we know that 40 children across the nation have died from flu so far this season. And sadly, the season is not over yet.  (Update: as of March 13th the number of pediatric deaths has risen to 48). Most years the average is closer to 100 pediatric flu deaths and as high as 49,000 flu-related deaths among adults.

Since pediatric flu deaths must be reported, as flu112315opposed to adult flu deaths, we tend to see news reports throughout the flu season, such as these: 

While we may never know the specifics of each case, what we do know is that the flu is completely unpredictable.  From season to season, we don’t always know exactly which strain will be most prevalent, which will be most dangerous, and who will suffer, be hospitalized or even die as a result of the flu.

The 60/40 factor in regards to pediatric flu deaths: In a previous season, 60% of pediatric deaths occurred among children who were in a high risk category, while 40% had no chronic health problems.

Read more…