Vaccine Update for Healthcare Providers

News and Views About Vaccine - Archive

• Efficacy and Effectiveness of Influenza Vaccines: A Systematic Review and Meta-Analysis Nov.2011
• Answering Questions About Human DNA and Human Proteins in Vaccines Oct.2011
• Influenza Vaccine Coverage June 2011
• Vaccines: Are They Natural? Dec. 2010

Efficacy and Effectiveness of Influenza Vaccines: A Systematic Review and Meta-Analysis

Charlotte A. Moser, Assistant Director, and Paul A. Offit, Director, Vaccine Education Center at The Children’s Hospital of Philadelphia 

The October 25, 2011 issue of The Lancet Infectious Diseases included an article titled "Efficacy and effectiveness of influenza vaccines: a systematic review and meta-analysis" by Michael T. Osterholm, Nicholas S. Kelley, Alfred Sommer and Edward A. Belongia. The article received a lot of attention from the media even though it didn’t provide new data about the influenza vaccine.

Highlights of the findings included:

• Influenza shots have about 59 percent efficacy against flu in healthy adults
• The nasal spray has 83 percent efficacy against flu in children 7 years of age or younger

While study authors promoted the continued use of the influenza vaccine, media reports mostly focused on the low efficacy in adults. Important points to make when discussing this study with patients who may have heard the news coverage:

• The analysis had very stringent requirements for including a study; therefore, of 5,707 publications, only 31 met the criteria for inclusion.
• Of the 31 studies reviewed, 17 were randomized controlled trials and 14 were observational.
• The analyzed studies were published between 1967 and 2011; therefore, they included some studies performed during years when vaccine strains may not have matched circulating strains.
• Research continues to be done to make better influenza vaccines:
  • Specific populations (e.g. Fluzone High-Dose for people 65 and older)
  • Adjuvants that may increase immune responses (e.g., oil-in-water study reviewed in October 2011 Vaccine Update and in the recent VEC webinar)
  • Quantities of antigen needed (e.g., Fluzone Intradermal, an intradermal influenza vaccine licensed by the FDA)
• While we know that the existing vaccine does not work as well as we may like:
  • For individuals: Some protection is better than no protection, and even people who still get influenza after being immunized are not likely to be as sick as those who are unimmunized.
  • For families and for the public’s health: Wider use of the influenza vaccine will lead to lower levels of transmission among family members and throughout our communities.

For more information, review the CDC’s "Flu Vaccine Effectiveness: Questions and Answers for Health Professionals"

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Answering Questions About Human DNA and Human Proteins in Vaccines

Charlotte A. Moser, Assistant Director, and Paul A. Offit, Director, Vaccine Education Center at The Children’s Hospital of Philadelphia

We often get questions about the use of cell lines from aborted fetuses in vaccines. In this article, we will address the issues and provide information about the resources available to share with parents.

Background

The only vaccines that are made in human cells are:

• Varicella
• Rubella
• Hepatitis A
• Rabies vaccine – the version known as Imovax®

The viruses were grown in cells obtained from elective terminations of pregnancies which occurred in the early 1960s. Since that time, the cell lines have been maintained in the laboratory. No further sources of fetal cells are necessary.

The questions about use of fetal tissues generally fall into one of three categories:

• Ethics and religion
• Vaccine safety related to remaining DNA
• Vaccine safety related to human proteins

Ethics and religion

Christian Science does not believe in using any vaccines; however, when outbreaks have occurred in communities with Christian Scientists, some have agreed to be vaccinated. Their concerns are not related to the use of fetal tissue, but rather to the use of modern medical interventions.

Given the position of the Catholic Church on abortion, some concerns have revolved around the use of cell lines from aborted fetuses. However, reviews by both the Vatican’s Pontifical Academy for Life and the National Catholic Bioethics Center have determined that vaccines grown in these cell lines do not defy the religion’s doctrine:

• Vatican statement
• Moral Reflections on Vaccines from Cells Derived from Aborted Human Fetuses

Vaccine safety related to remaining DNA

The concern about DNA is that it can cause changes in the vaccine recipient’s DNA. This is unlikely for two reasons:

• Most of the foreign DNA is destroyed during the process of making the vaccine; the minimal amount that remains (trillionths of a gram) is highly fragmented. Because DNA is fragmented, it cannot possibly create a whole protein.
• The chance that foreign DNA would incorporate into a region of cellular DNA (i.e. promoter region) is about zero. In fact, if the trace quantities of residual DNA present in vaccines (and other biologicals) could incorporate itself into host DNA behind a promoter region and be stably expressed, studies of gene therapy would have been much more successful.

Vaccine safety related to human proteins

The concern about contamination of vaccines with human proteins seems to be relatively new. Because viruses are purified during vaccine production, it is unlikely that proteins from the human cells used to grow them would survive intact or in quantities sufficient to cause harm.

Resources for parents

• Vaccine Education Center website – Hot Topics – this section of the VEC website was recently reviewed and updated; just use the list on the left side of the page to navigate to the topic of interest.
• Parents PACK website:
  • Vaccine Science
  • DNA in Vaccines
• "Vaccines and Your Child: Separating Fact from Fiction" – published by Columbia University Press; this guide for parents is divided into two main sections: questions parents have about vaccine safety, and vaccine-specific chapters.
• References related to religion – compiled by Immunization Action Coalition (IAC)
• Brief discussion and references related to religion – offered by the Institute for Vaccine Safety

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Influenza vaccine coverage

Charlotte A. Moser, Assistant Director, and Paul A. Offit, Director, Vaccine Education Center at The Children’s Hospital of Philadelphia

The CDC published "Interim results: State-specific influenza vaccination coverage—United States, August 2010-February 2011" in MMWR (2011; 60: 737-747). The report showed that about the same number of people got an influenza vaccine this year as they did last year during the H1N1 pandemic. Specific comparisons are outlined in the table:

*Data from 7 states not included: CA, LA, MI, NV, OK, OR, and SD

The good news ...

Given the subject fatigue following H1N1 and the lack of urgency associated with a pandemic situation, we should celebrate the maintenance in coverage among most groups of people and the 7 percent increase in coverage of children.

The reality ...

However, we need to acknowledge that with the exception of people 65 and older, we are still not even immunizing 1 of every 2 people in the various age groups. We are just about there for children 6 months to 17 years.

Because the vaccine strains have not been changed, people have already started to wonder about the need for an influenza vaccine this fall. While it is true that we typically immunize because of new strains circulating each year, this is not the only reason to immunize:

• The vaccine is typically only about 70-85 percent effective. A second dose with the same influenza strains will increase that percentage
• Waning immunity has been shown in some populations, such as the elderly
• As noted above, less than half of the population actually got the vaccine last season

The other side of the coin ... disease

Based on CDC surveillance data:

• About 55,000 patient samples tested positive for influenza
• About 561,000 outpatient visits were for influenza-like illnesses this season
• This season 106 children died from influenza—106 families lost their child, 106 practices lost a patient, 106 schools lost a student. Did any of them imagine that influenza would kill someone they know? Probably not.

We know that all cases of influenza are not laboratory confirmed and not everyone with influenza seeks medical attention, so these disease estimates are probably low.

Where would these numbers be if we were able to immunize a higher percentage of the population?

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Vaccines: Are they natural?

Paul A. Offit, Director, Vaccine Education Center at The Children’s Hospital of Philadelphia , Dec. 2010

Many of today’s consumers crave organic, all-natural, or free-range products. Willing to pay more and drive further to get these products, they believe they are keeping their families healthy. Some of these same people forego vaccines claiming that they are not natural.

So, what is natural?

According to the Merriam-Webster dictionary, natural means “being in accordance with or determined by nature.” Viruses and bacteria are natural; diseases caused by them are natural.

Because vaccines are made using parts of the viruses and bacteria that cause disease, the ingredient that is the active component of the vaccine that induces immunity is natural. However, critics point to other ingredients in vaccines or the route of administration as being unnatural.

Vaccine ingredients

“Green our vaccines” is a common mantra of those who believe that the ingredients in vaccines are harmful—and unnatural. However, vaccine vials contain well-characterized ingredients in known quantities.

Vaccines contain three types of ingredients other than the virus or bacterium of interest:

• Adjuvants enhance the immune response, typically allowing for lesser quantities of the viral or bacterial components to be used in the vaccine. Aluminum is an example.
• Stabilizers protect the proteins in the vaccine from being degraded during manufacture and transport. Gelatin is an example.
• Preservatives keep the vaccine from becoming contaminated. The mercury-containing preservative thimerosal is perhaps the most well-known, although it has been removed from all childhood vaccines except some multi-dose vials of influenza vaccine given to older infants and children.
• For in-depth discussions, consult the following Q&As:
  • “Vaccine Ingredients: What You Should Know” - English; Spanish
  • “Aluminum: What You Should Know” - English; Spanish
  • “Thimerosal: What You Should Know” - English; Spanish

Some wonder about the amount of different additives in vaccines or the cumulative effect from several vaccines. This is a valid concern; in fact, the Swiss chemist Paracelsus coined the phrase, “the dose makes the poison.” However, the good news is that the quantities of ingredients in vaccines are determined to be the lowest amounts necessary and when vaccines are given together, they must be studied together. So the quantities of ingredients in vaccines have been determined to be safe.

Route of administration

Viruses and bacteria typically enter the body through our noses or mouths. With the exceptions of the oral rotavirus and intranasal influenza vaccines, most vaccines are given as a shot. While at first glance the injections appear to be different or “unnatural,” they are not when you consider what happens in each case.

When viruses or bacteria enter the body through the nose or mouth, they are detected by cells of the immune system which line the surfaces of these areas of entry. These “foreign invaders” are ingested by immune cells and processed in lymph nodes in the region of the infection. The immune response has two aspects, local and systemic. The immune cells are produced near the site of the infection, but they are dispersed throughout the body via the bloodstream. After the infection has been resolved, a small number of immune memory cells continue circulating to monitor for future infections. Because these memory responses are specific, subsequent exposures to the same virus or bacterium generate a quicker and stronger immune response that completely prevents or significantly lessens the effects and duration of illness.

Vaccines are no different. Although common belief is that vaccines are injected directly into the bloodstream, they are actually administered into muscle or the layer of skin below the dermis where immune cells are produced and circulate as occurs following natural infection.

In conclusion

The active ingredients in vaccines are the parts of the viruses or bacteria to which we make an immune response. The additional ingredients are determined to be the lowest plausible quantities and are studied as part of the vaccine during safety testing. The immune system responds in the same way it would to the virus or bacteria following unexpected introduction. So while not natural in that they are given at specified times, vaccines offer a controlled way to protect ourselves from the viruses or bacteria that cause illness.

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