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How Do We Know Vaccines are Safe?

August 15, 2018 8 comments

Vaccinate Your Family_MomGrandmaLittleGirlToo often, we hear misinformation about vaccines and their safety. Some people claim that they are not tested for safety before being licensed and recommended for use in people in the United States. Others say that vaccines are not held to the same safety standards as drugs, when in fact they are held to a higher standard. And some others wrongly proclaim that vaccines are not monitored for safety after they are licensed by the U.S. Food and Drug Administration (FDA) and recommended for the public by the Centers for Disease Control and Prevention (CDC), as they are unaware of the strong vaccine surveillance systems we have in place in the U.S.

The United States has the safest, most effective vaccine supply in its history.

Below, we offer an overview of how vaccines are tested and monitored for safety and effectiveness:

Clinical trials

Vaccines are one of the most thoroughly tested medical products available in the U.S. Before a vaccine can be considered for approval by the FDA, a vaccine manufacturer must show it is safe and effective through clinical trials. Developing a new vaccine begins with exploratory stage and pre-clinical stage before advancing to three stages of clinical trials. Together, this scientific process can take over a decade and cost millions of dollars. The FDA then examines these studies and determines whether a vaccine is safe, effective, and ready to be licensed for use. The FDA only licenses vaccines that have data that shows that the vaccines’ benefits outweigh the potential risks. If there is any question about the data, or any holes in the data, the FDA will request further studies before approving the vaccine.

Four monitoring systems 

After a vaccine is licensed for use in the U.S., there are four systems in place that work together to help scientists monitor the safety of vaccines and identify any rare side effects that may not have been found in clinical trials. Even large clinical trials may not be big enough to find very rare side effects. For example, some side effects may only happen in 1 in 100,000 or 1 in 500,000 people. Second, vaccine trials may not include certain populations like pregnant women or people with specific medical conditions who might have different types of side effects or who might have a higher risk of side effects than the volunteers who got the vaccine during clinical trials.

Vaccine Adverse Events Reporting System (VAERS)

VAERS is a passive reporting system. That means it relies on individuals to report vaccine reactions. Anyone can report a reaction or injury, including healthcare providers, patients and patients’ representatives, such as caregivers or attorneys. The system is co-managed by the FDA and the CDC. However, it is important to note that VAERS data alone can’t be used to answer the question, “Does a certain vaccine cause a certain side effect?” This is because adverse events reported to VAERS may or may not be caused by vaccines. There are reports in VAERS of common conditions that occur just by chance after vaccination. Further investigation may find no medical link between vaccination and these conditions. Instead, the purpose of VAERS is to see if unexpected or unusual patterns emerge, which may indicate a vaccine safety issue that needs to be researched further.

The Vaccine Safety Datalink (VSD)

Established in 1990, VSD is a collaboration between the CDC’s Immunization Safety Office and eight health care organizations across the country. It conducts studies based on questions or concerns raised from the medical literature and reports to VAERS. In addition, when new vaccines are recommended or if changes are made in how a vaccine is recommended, VSD will monitor the safety of these vaccines.

The Clinical Immunization Safety Assessment Project (CISA)

CISA, which was created in 2001, is a national network of vaccine safety experts from the CDC’s Immunization Safety Office, seven medical research centers and other partners. CISA addresses vaccine safety issues, conducts high quality clinical research and assesses complex clinical adverse events following vaccination. CISA also helps to connect clinicians with experts who can help consult on vaccine safety questions related to individual patients.

The Post-Licensure Rapid Immunization Safety Monitoring System (PRISM)

PRISM is a partnership between the FDA’s Center for Biologics Evaluation and Research and leading health insurance companies. It actively monitors and analyzes data from a representative subset of the general population. PRISM links data from health plans with data from state and city immunization information systems (IIS). PRISM has access to information for over 190 million people allowing it to identify and analyze rare health outcomes that would otherwise be difficult to assess.

These four post-licensure monitoring systems have been able to address several important issues related to vaccines and their safety, including:

The Department of Health and Human Services (HHS) and its agencies, health insurance companies, scientists, healthcare providers, and other public health and medical groups are all dedicated to ensuring people of all ages are protected against serious infectious diseases by a safe, effective supply of vaccines.

Protecting Myself and My Child against Vaccine-Preventable Diseases during Pregnancy

August 6, 2018 3 comments

By Erica DeWald, Director, Advocacy, Every Child By Two

Here at Every Child By Two, we practice what we preach. That’s why I got both a Tdap and influenza vaccine when pregnant with my first child (who is fully up-to-date on his childhood vaccines). Now that I’m expecting my second baby, I didn’t hesitate to get vaccinated again.

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Why do I choose to get vaccinated?

Vaccines during my pregnancy have the ability to protect not only me, but my child as well. Infections such as flu and whooping cough, also known as pertussis, are not just a threat to me. They can also be extremely dangerous, and even deadly, to newborns.

Why get vaccinated against whooping cough?

Whooping cough is a highly contagious respiratory disease that spreads easily from person-to-person through coughing and sneezing. Symptoms can be less severe in vaccinated people and older children and adults, so adolescents or adults may unknowingly pass the infection onto vulnerable infants.

In young children, the cough can be so severe that it can cause a child to gag, turn blue, vomit or pass out. A gasp for air after a coughing fit can sometimes produces a loud “whoop” sound, though it is not uncommon to have whooping cough without producing the “whoop” sound.  This intense coughing phase can last as long as 10 weeks.

Half of all children who get whooping cough under a year of age end up in the hospital. Some will suffer lifelong complications and one of every 100 will die.

Why get vaccinated against flu?

Changes in my immune, heart, and lung functions during pregnancy make me more likely to get ill and suffer severe complications from illnesses as compared to non-pregnant women. In fact, as a pregnant woman, I am five times more likely to suffer complications or death from flu compared to non-pregnant women.  Additionally, if I fall ill during pregnancy, I have a greater chance of hospitalization, spontaneous abortion or complications that can directly impact the health of my baby such as preterm labor and delivery, and low birth weight babies.

In children, the highest incidence of hospitalization due to influenza is among infants younger than 1 year, with those younger than 6 months at highest risk. On average, about 100 children die from flu each year in the U.S. and thousands more are hospitalized.

Getting vaccinated during pregnancy also provides my child with protection during his first weeks and months.

By getting my vaccines in pregnancy when recommended by the Centers for Disease Control and Prevention (CDC), the American College of Obstetricians and Gynecologists (ACOG), and the American College of Nurse Midwives (ACNM), I can lessen my child’s chances of contracting these diseases when he is most vulnerable (and before he receives his own vaccines):

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How do I know vaccines are safe for me and my child?

Experts carefully reviewed the safety data of the whooping cough vaccine before recommendation that women receive a Tdap vaccine during each pregnancy.  They concluded that the vaccine was safe for both pregnant women and their babies and there is a long list of published safety studies that can be reviewed here.

Additionally, science supports the safety of flu vaccination for pregnant women and their babies, and the flu shot has been safely administered to millions of pregnant women over many years.  While the scientific community will continue to gather data on this topic, various studies, such as those detailed below, already indicate that it is safe to administer the flu vaccine in pregnancy.

For now, I’m off to find a flu vaccine in order to give my child some protection against the disease before he’s born and flu season is in full swing!

Find more information on vaccines in pregnancy on these websites:

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How Flu Strains are Selected for the Seasonal Flu Vaccine Each Year

March 14, 2018 5 comments
SereseMarotta_FamiliesFightingFlu-300x300by Serese Marotta, Chief Operating Officer of Families Fighting Flu 

 

The Centers for Disease Control and Prevention (CDC) recommends that everyone ages 6 months and older, with rare exception, get an annual flu vaccine. But did you ever wonder how the flu strains are selected for the seasonal vaccine every year?

A lot more goes into the decision than you might think!

Seasonal flu vaccines contain three (trivalent) or four (quadrivalent) flu strains. Because flu is a complex, dynamic virus that is constantly changing, there are more than 100 monitoring centers in over 100 countries located across the globe that monitor flu activity on a year-round basis to identify which flu strains are circulating.

These centers receive and test thousands of influenza virus samples from patients. They then send representative virus samples to five World Health Organization (WHO) Collaborating Centers for Reference and Research on Influenza, located in Atlanta, GA (i.e., the CDC); London, United Kingdom; Melbourne, Australia; Tokyo, Japan; and Beijing, China. The surveillance data gathered from these samples, along with other information, are used to make a recommendation on which flu strains should be included in the upcoming year’s seasonal flu vaccine.

Contrary to popular belief, the flu vaccine is not just based on last year’s flu viruses. Three general sources of information are considered in the selection of flu strains for the seasonal flu vaccine:

 

  • Surveillance data represents information gathered from the influenza monitoring centers that collect virus samples from patients. Experts use this information to determine which flu strains are circulating and where.
  • Laboratory data refers to antigenic characterization of the flu viruses in a laboratory, which simply means the identification of specific molecular structures on the influenza virus that are recognized by our immune systems and elicit an immune response. The antigen is the “invader” (i.e., in this case, the flu virus) that causes our immune systems to launch an attack through the formation of specific antibodies. Antibodies are what our bodies produce following flu vaccination so that it’s properly “armed and ready” to recognize and fight that specific flu virus if and when we’re exposed.
  • Genetic characterization of flu viruses may also be considered in the selection of vaccine strains. This refers to “mapping” of the genetic codes that make up each flu strain, which allows the experts to monitor changes in circulating flu viruses.
  • Data from clinical studies on vaccine effectiveness are also considered.

With this robust amount of data in hand,  the WHO then meets twice per year to make a recommendation for flu vaccine strains for the upcoming season: once in February to recommend flu strains for the Northern Hemisphere seasonal flu vaccine, and again in September to recommend flu strains for the Southern Hemisphere seasonal flu vaccine. But it doesn’t stop there! Each country then considers the WHO recommendation, reviews the available information, and makes their own decision on which flu strains to include in their country’s seasonal flu vaccine.

In the U.S., once the WHO makes their recommendation for flu strains for the upcoming year’s seasonal flu vaccine, an advisory committee from the U.S. Food and Drug Administration (FDA) meets in February or March to review the WHO’s recommendation and supporting information and vote on the final selection of flu strains. The role of the FDA is an important one, because once the flu strains are selected, the FDA produces materials in their laboratories that are critical for actually producing the flu vaccines. For instance, the FDA provides vaccine manufacturers with the seed viruses and the potency reagents needed to ensure that flu vaccines made by one manufacturer are similar to those made by another. The FDA also conducts quality control measures by ensuring that batches (referred to as “lots”) of flu vaccines released by the manufacturers meet appropriate standards and reflect the correct genetic composition.

Following the selection of flu strains for the seasonal vaccine and receipt of the appropriate materials and information from the FDA, private sector manufacturers begin the process of making the vaccines. All flu vaccines in the U.S. contain the same flu strains, i.e., the flu vaccine available in New York contains the same three or four flu strains as the vaccine that’s available in California. And it’s important to remember that all flu strains (influenza A or B) can be potentially dangerous, regardless of an individual’s health status, and are capable of causing serious illness, hospitalization, or even death.

Influenza is a vaccine-preventable disease that has the ability to affect all of us around the world, which is why it remains such a pressing global public health issue. Seasonal flu vaccines may not be perfect, but given the complexity of flu viruses and their ability to change and mutate frequently, the U.S. does have a solid, scientifically-based approach for flu vaccine development. While much research and development is being done for a universal flu vaccine, the possibility of this technological advancement is still many years off.  In the meantime, let’s not forget all the hard work and research that goes into helping to protect us with the currently available seasonal flu vaccines. And if you’re wondering “why bother” with a flu vaccine that may be substantially less than 100% effective, let’s remember that something is better than nothing, especially when it comes to your life or the life of a loved one.

More in-depth information on how flu strains are selected for the seasonal flu vaccine every year are available from the CDC and FDA


FFF logo_R copyAbout Families Fighting Flu:  Families Fighting Flu (FFF) is a national, nonprofit, 501(c)(3) volunteer-based advocacy organization dedicated to protecting the lives of children and families by helping to increase annual influenza vaccination rates, especially among children 6 months and older and their families.  Our members include families whose children have suffered serious medical complications or died from influenza, as well as healthcare practitioners and advocates committed to flu prevention.  In honor of our children, we work to increase awareness about the seriousness of influenza and to reduce the number of hospitalizations and deaths caused by the flu each year.

Young Hockey Player’s Death A Flu Warning

January 22, 2018 3 comments

By Amy Pisani, Executive Director of Every Child By Two/Vaccinate Your Family

Each of us has a tipping point; the moment when a news story becomes personal, more impactful and perhaps spurs action.

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Every Child By Two Executive Director, Amy Pisani, with her son Nicholas, a fellow hockey player from CT.

After hearing of the tragic death of 10-year-old Nico Mallozzi, an ice hockey player from a neighboring town who died Sunday from complications related to flu, I immediately reached out to our hockey league president to ask him to urge our teams to implement the same flu protocol that Nico’s team is now doing: Stay home if you have symptoms of influenza, don’t share water bottles and shake hands post game with gloves on. Thursday evening our league distributed Nico Mallozzi # 7 memorial stickers for every player’s helmet.

According to friends and family writing online, Nico was a sweet, happy, healthy child from New Canaan, CT. He had traveled to upstate New York to cheer on his team during a hockey tournament in which he did not participate because he was feeling sick.  Nico was hospitalized on his way home and died the same day, reportedly from influenza and its complications.

As the executive director of Every Child By Two, a national non-profit organization whose mission is to ensure that all families are protected from vaccine-preventable diseases, it saddens me to learn of yet another family suffering the devastating loss of a child. As a fellow hockey mom, this tragedy resonates deeply.  Anyone with a child on a team knows that hockey families are a tight group. From fall to early spring, we travel the region at all hours of the day and night in support of our children. We cherish our children’s teammates, who we watch grow up from wobbly “learn to skaters” to dedicated players who often commit five or six days a week to practice and playing games, building lifelong friendships.

Nico’s tragic death is a poignant reminder that children of any age, even those who are healthy and athletic, can be taken by flu in a heartbeat. 

Each year, the Centers for Disease Control and Prevention warns us that approximately 100 children will die from influenza every season. Sadly, as of last week, here in the U.S. there have already been 30 children who died from flu so far this season, and this number will continue to climb, as we are nowhere near the end of this outbreak. Unfortunately, these kinds of statistics don’t always resonate with the public and as a result, health advocates are challenged to find ways to spur families to take the time to vaccinate everyone 6 months and older against flu each and every year.

To make matters worse, there are mixed messages about the effectiveness of influenza vaccines and getting across the idea that some protection from the vaccine is better than none is often difficult. As with any infectious disease, community prevention is of paramount importance. Since no vaccine is 100 percent effective and not everyone is able to be vaccinated due to age or underlying medical conditions, we must provide a barrier around one another to keep diseases from taking the lives of children like Nico.

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It’s not too late to get a flu shot for yourself and your family.

While the peak of flu activity varies from year to year, it often occurs between December and February, and can last as long as until May. Although 12,000 to 56,000 people die each season, influenza vaccination has been shown to reduce the risk of flu-associated death by 65 percent among healthy children and by 51 percent among children with underlying high-risk medical conditions. Other research indicates that adults benefit from repeated flu vaccination year after year. The study found flu vaccination was 74 percent effective in preventing intensive care unit admissions in older individuals and 70 percent effective in preventing deaths among older adults.

These statistics matter and they all say the same thing; protect your entire family from flu by getting vaccinated against this potentially deadly disease every year.

For more information on this year’s flu season, visit:

 


This editorial was originally published in the Hartford Courant.

 

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…

Most Popular Posts of 2017 Address Flu, Vaccine Safety, Disease Outbreaks and Maternal Vaccines

December 27, 2017 Leave a comment

As we look back at the success of the Shot of Prevention blog this past year, we’re especially grateful to our blog readers, contributors and subscribers.

Whether you’ve shared a post, shared your story, or shared your expertise, we recognize that our growth and success would not have been possible without your support. Thanks to you, our posts are helping people to make important immunization decisions for themselves and their families.

In these final days of 2017, we hope that you will revisit the top ten posts from the past year and share them with others in your social networks.  

1)  3 Things I’ve Learned Since Losing My Son To Flu

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It’s been eight years since Serese Marotta of Families Fighting Flu lost her five-year-old son, Joseph, to the flu. She’s not the same person she was eight years ago. Today, she sees things through a different lens as a bereaved parent. Losing a child is devastating, but she feels a responsibility to pass on some of the lessons she’s learned through her personal tragedy, which she does in her article here.

 

2)  10 Things Parents Who Don’t Vaccinate Their Kids Should Know

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In some cases, children who have suffered with a preventable disease were unvaccinated.  This could be the result of parents who did not have access to certain vaccines, parents who willfully refused a particular vaccine, or it could because they were too young to be fully vaccinated. After Riley Hughes passed away in the arms of his parents when he was just 32 days old, his parents made it their mission to educate people about the dangers of whooping cough, and promote the need for vaccination. In a plea to parents who still choose not to vaccinate, Riley’s mom posted the following list of “things to know” here.

 

3)  Even With All Our Modern Medicine I Watched My Sister Die From Flu

lizaLiza was healthy and only 49 years old when she contracted flu. She sought medical care early. She was cared for at a good hospital in a major city.  She had no other infections. And she was unvaccinated. To say that her death was a surprise to her brother is an understatement.  And yet her brother, Dr. Michael Northrop is a pediatric intensive care physician. His story traces the clinical course of Liza’s illness, and expresses the grief he felt as he helplessly watched his sister  succumbs to an illness that even modern medicine can’t always save us from. To read his story, click here.

 

4) Take It From This Mom, The Flu Is No Joke

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After her four-year old daughter is rushed to the emergency room, she writes a warning to others.  “The words just the flu need to be eradicated from our lexicon. Because this? This is the flu. There’s no ‘just’ about this. It was terrifying. It was the most helpless I’ve ever felt as a mommy. And it was potentially deadly.  All because I was too busy to get our flu shots.” Read the full story here.

 

5) Flu Vaccine Benefits Go Beyond Effectiveness of One Strain

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Amid speculation about how effective the flu vaccine will be this year, Dr. LJ Tan addresses some of the public’s most prominent concerns. He starts with a basic explanation of flu and flu vaccines, discusses the factors that play into vaccine effectiveness, and addresses rumors about this year’s flu vaccines. To gain a better understanding, read more here.

 

6) How My Sister Helped Save My Daughter From Whooping Cough

As a Medical Director responsible for Community Health and Prevention at Intermountain Healthcare in Salt Lake City, Utah, Tamara Sheffield is a huge advocate for SOTI_Pertussis_FBimmunizations. She is especially appreciative of maternal immunizations, which she considers one of today’s most promising new preventive health strategies. But her reasons go beyond her professional understanding of how maternal flu and Tdap vaccines pass on protective antibodies to newborns. Her surprising story ends with a twist involving her own daughter who nearly died from whooping cough when she was just three weeks old. Read it here.

 

7) Multiple Vaccine Oversight Committees Ensure Our Public Safety

While 2017 brought a lot of uncertainty about health services in this country, Dr. Dorit Reiss, Professor of Law at the University of California Hastings College of Law, explains 178_NFID_Vaccine_Safety_infograms_2_FINALwhy the public should remain confident in vaccine safety. In this post she reviews the specific ways in which vaccine safety is regulated in the U.S., and the oversight committees that monitor vaccines pre and post licensure. Her scrutiny explains that it would be hard to hide a problem if one existed, and that when problems do occur, they are quickly discovered and addressed. To learn more about vaccine safety oversight, read the full post here.

 

8) Why Should Vaccinated Individuals Worry About Measles Outbreaks

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With various measles outbreaks reported across the U.S. and the world in 2017, it’s important to understand why vaccinated individuals should be concerned. Many people mistakenly think that vaccinated individuals are not at risk during outbreaks. However, when it comes to infectious diseases like measles, one person’s decision not to vaccinate can negatively impact the health of others and this post explains how.

 

9) Five Things I’ve Learned About Vaccines Through 21 Years of Parenting

HowHerdImmunityWorksWe’ve all received plenty of unsolicited advice about how to care for our children. However, when making health decision for our families we should rely on evidence based research and credible information from reputable sources. In this post, I share five of the most important things I’ve learned about vaccines through my journey as a parent and immunization blogger. Spoiler alert: it begins with science and it ends with action.

 

10) Five Things Expectant Parents Need to Know About Vaccines in Pregnancy

SOTI-PregnancyCoverFBWhile well-meaning friends and family will provide a constant stream of advice on what to do and what to avoid while pregnant, all this information can be overwhelming. Expectant couples should rely on credible medical sources such as the CDC, the American College of Obstetricians and Gynecologists (ACOG), and the American College of Nurse Midwives. This blog post reviews the 5 things these trusted organizations say about the flu and Tdap vaccines routinely recommended during pregnancy. Learn more here.

 

We hope you have found our content to be engaging and informative.  We have exciting changes planned for Shot of Prevention in 2018 in hopes of engaging even more people in these important immunization conversations in the years to come.  

If you have suggestions for topics you would like us to address in 2018, or you would like to contribute a guest post for publication, please email shotofprevention@gmail.com.

Also, if you want to receive important immunization news and join in our online discussions, be sure to “Like” our Vaccinate Your Family Facebook page, follow our @ShotofPrev Twitter feed and subscribe to Shot of Prevention by clicking the link on the top right of this page.

Thanks again for your continued support and best wishes for a happy and healthy new year!

Flu Vaccine Benefits Go Beyond Effectiveness of One Strain

December 11, 2017 3 comments
LJ TanGuest post by Litjen (LJ) Tan, MS, PhD; co-chair and co-founder of the National Adult and Influenza Immunization Summit.

 

There seems to be a lot of speculation recently about how effective the influenza (flu) vaccine will be at preventing cases of influenza this season.

We have heard suggestions that the vaccine may only be 10% effective against flu this year, that there may be mismatches in the vaccine compared to the influenza strains that are circulating, and thus, that the vaccine is not worth getting.

To address these concerns I will start with a basic explanation of flu and flu vaccines, and then discuss the factors that play into vaccine effectiveness.

First, let me say that influenza is a serious respiratory infection that is responsible for about 30% of all the respiratory infections during the winter season. When I say serious, I mean that flu can keep you down for a week or more, and you will feel completely miserable. Additionally, each year thousands of people of all ages die from flu in the U.S.; it can be very dangerous. So, that office colleague who said that he was out with the flu yesterday very likely did not have influenza. Not fully understanding the dangers of flu is why some people fail to see the value of flu prevention.  

Flu is caused by multiple strains of influenza viruses that circulate during the winter season; specifically, we have influenza type A (with the H3N2 and H1N1 strains) and influenza type B (there are two type B strains that can circulate and currently 90% appear to be the Yamagata lineage, but since it is still so early in the season and sample sizes are small, this data point may not be statistically significant). Because these strains of flu viruses can switch every season in terms of dominance, and can also mutate, manufacturers need to develop a new influenza vaccine every year and people need to be re-vaccinated each year.

To be clear, the vaccine development process is the same every year, it is just that the starting, or “seed”, vaccine virus that we immunize against has to be identified before it can be used to develop our country’s annual vaccines.

When that seed virus is identified, it is then amplified (or passaged) to develop more seed virus. Then that seed virus is further amplified to create the large quantities of vaccine virus that we ultimately need to prepare an adequate supply of vaccines to protect our population. That amplification of the seed virus, and the making of large amounts of vaccine virus, can occur in eggs, which is the more traditional way, or it can also occur in cell cultures. So there needs to be four seed viruses developed and amplified to create influenza vaccines – an H3N2 seed, an H1N1 seed, and the two B seed viruses.

So why do we keep hearing people say that this year’s flu vaccine may only be 10% effective? Where did that suggestion come from?

When we say that a flu vaccine is 10% effective, what we usually mean is that it was effective in preventing 10% of cases of influenza in those who were vaccinated. This 10% number that you may have heard is actually a data point from Australia, and it’s not against all strains of flu, but specifically against the H3N2 strain that dominated the southern hemisphere this past flu season. If you look at the Australian data for all influenza, the vaccine effectiveness goes up to 33%. Agreed, that’s not great for Australians (although, it’s still better than no protection), but is looking at the Australian data truly reflective of what might happen in the US?

It’s unlikely, and here’s why. Read more…