Parents’ vaccine fears and how to address them

©Copyright 2010

The issue

• All pediatricians and public health authorities recommend a series of immunizations for all children

• Some parents refuse immunizations for their children or want to alter the recommended schedule

• How should pediatricians respond to “vaccine hesitancy” or refusal?

How common is vaccine refusal?

• Survey of 2521 parents with children <18

• Jan 2009

• Response rate: 62%

• Outcome measures:– Parental view on vaccine safety– Vaccine refusal

Results

• 11.5% of parents had refused at least one recommended vaccine

• Of those who’d refused at least one:– 56% HPV– 32% varicella– 32% meningococcal conjugate– 18% MMR

Parental views on vaccine safety

• Vaccines offer good protection 90%

• I generally follow my doctor’s

advice on vaccines 88%

• I’m concerned about adverse effects 54%

• Parents should have the right to

refuse any vaccines 31%

• Some vaccinations cause autism 25%

• My kids don’t need to be vaccinated

for rare diseases 11%

Freed et al. Pediatrics. 2010.

Why do parents refuse vaccines?

• Common fears about vaccines– Too many immunizations overwhelm the immune system– Vaccines (especially MMR) cause autism– Vaccines contain mercury– Vaccine-induced immunity will wane. Natural infection is better

• We address each of these…

Will multiple vaccinations, especially in one visit, impair a

baby’s immune system?

The number of vaccinations over the last century has steadily

increased…

Offit et al. Pediatrics. 2002.

But the total number of proteins and polysaccharides in the vaccines

has diminished dramatically

Offit et al. Pediatrics. 2002.

Bottom line

• Kids today get more vaccines but fewer antigens to challenge their immune system

• Their immune systems can handle it

• The average child could respond adequately to 10,000 antigens at once

• 10 vaccinations use up about 0.1% of a child’s immunologic capability

What about newborns with impaired immune systems?

Can immunization cause illness

• A live-virus vaccine can cause illness in an immunocompromised baby

• Live-virus vaccines are not routinely recommended before age 1*

• Even for immunocompromised children, the risk from live-virus vaccines is generally lower than risk of disease

• Check with an infectious disease specialist

*MMR is given to babies before international travel

Does illness impede body’s ability to react to antigen?

Many studies have looked at this

• Led to comprehensive report by the Institute of Medicine:– Stratton KR, Wilson CB, McCormick MC. Immunization safety

review: Multiple Immunizations and Immune Dysfunction• Institute of Medicine. Washington, D.C: National Academy Press;

2002

• Studies find no increased risk of infection following multiple immunizations

Study of vaccines and illness

• 496 children

• Randomized to early or late vaccination– Early group – DPT/IPV at 60 days

– Late group – DPT/IPV at 90 days

• Studied all illnesses before and after immunization in both groups

Otto et al. J Infect Dis. 2000.

More illness before vaccines, not after

Otto et al. J Infect Dis. 2000.

Incidence of illness after MMR

• 2025 children 12-23 months who were admitted with an infection

• 1865 control cases who had received an MMR

• Compared the two groups to see if infection was related to the MMR shot

Stowe at al. Vaccine. 2009.

Infection rate lowest right after MMR

Stowe at al. Vaccine. 2009.

MMR and autism

• Association based upon one small study, published in The Lancet, in 1998

• Since then, numerous studies have been done showing no association, the Lancet study has been retracted, and the author stripped of his license in the UK

MMR for kids with autism and controls

DeStefano et al. Pediatrics. 2004.

Danish study

• Retrospective follow-up study

• All 537,303 children born, 1991-98

• 440,655 (82%) had received MMR– 316 children diagnosed with autism– 422 children diagnosed with autism spectrum disorders

Madsen et al. N Engl J Med. 2002.

No association between the age at the time of vaccination, the time since vaccination, or the date of vaccination and the development of autistic disorder.

Madsen et al. N Engl J Med. 2002.

IOM review

• No epidemiological evidence for association or MMR and autism

• No plausible biologic model

• No animal model

IOM – Immunization and safety review: vaccines and autismhttp://www.iom.edu/Reports/2004/Immunization-Safety-Review-Vaccines-and-Autism.aspx

What about thimerosal?

• Thimerosal is a mercury-containing preservative that used to be in many vaccines

• Since 2001, it is not used in any vaccine except multi-dose vials of influenza vaccine

Gross L. PLoS Biol. 2009.

Is natural disease better than immunization?

Is natural disease better than immunization?

• Natural disease may confer more lasting immunity (though not 100% immunity)

• Natural disease associated with dangers that are not seen with vaccines, e.g.– Mumps orchitis– Measles meningitis– Varicella pneumonia

Does immunity wane?

• Evidence for waning immunity with some vaccines, not others– Varicella– Pertussis

Varicella rates rise in older children after vaccine introduced

Chaves et al. N Engl J Med. 2007.

Risk of varicella infection increases with time after vaccination

Chaves et al. N Engl J Med. 2007.

Pertussis cases on the rise in adolescents – U.S. 2003

Hopkins RS, et al. Centers for Disease Control and Prevention. Summary of notifiable diseases-United States 2003. MMWR 2005;52:55.

Waning immunity in pertussis

• CDC now recommends a second varicella immunization at 4-6 years

• Many countries now recommend pertussis re-immunization every 10 years

Lopez. Pediatrics. 2006.AAP Committee on Infectious Disease. Pediatrics. 2006.

Is two doses enough?

Outbreak in Arkansas

• September 2006

• 97% of students had been vaccinated

• 39% had received two doses

• Allowed comparison of 1 versus 2 doses

Gould et al. Pediatr Infect Dis. 2009.

Outbreak in Arkansas

• Of the 85 children who got varicella– 53 had received one dose of vaccine– 25 had received two doses– 6 had no vaccine but prior varicella disease

Gould et al. Pediatr Infect Dis. 2009.

2nd dose increases immunity

• Attack rates among children with:– One dose of vaccine and no disease history: 14.6%– Two doses and no disease history: 10.4%

• Vaccine efficacy:– 85.4% among those with one dose– 89.1% among those with two doses

• Two doses better, but not 100% effective. Natural immunity is not 100% effective, either

Gould et al. Pediatr Infect Dis. 2009.

Most pediatricians have experience with vaccine

hesitancy or refusal

• 74% of physicians have had parents refuse vaccinations during the past year

• 16% of pediatricians refuse to continue caring for vaccine refusers at least some of the time

• 32% of parents who initially refused a vaccine changed their mind

American Academy of Pediatrics

How to approach a resistant parent

• Listen carefully and respectfully• Honestly share what is and isn’t known about risks• Discuss vaccines one by one• Present the risks of vaccine not in isolation, but compared

to risks of no vaccine• Take steps to reduce the pain of the shots• Consider scheduling shots one at a time (even though this

is not recommended by the CDC’s Advisory Committee on Immunization Practices)

Diekema and Committee on Bioethics. Pediatrics. 2005.

Approach to resistant parents

• Keep talking about immunization at each visit; people change their minds

• Think very carefully before dismissing a family. Children need and deserve access to good care, regardless of their parents’ decisions about vaccination

• Contact state authorities only in the event of possible imminent harm, like an outbreak of disease in the community

Diekema and Committee on Bioethics. Pediatrics. 2005.

ResourcesChaves SS, Gargiullo P, Zhang JX, Civen R, Guris D, Mascola L, Seward JF. Loss of vaccine-induced immunity to varicella over time. N Engl J Med. 2007 Mar 15;356(11):1121-9.

Diekema DS. Choices should have consequences: failure to vaccinate, harm to others, civil liability. Michigan Law Review.

Diekema DS and AAP Committee on Bioethics. Responding to parental refusals of immunization of children. Pediatrics. 2005 May;115(5):1428-1431 .

Freed GL, Clark SJ, Butchart AT, Singer DC, Davis MM. Parental vaccine safety concerns in 2009. Pediatrics. 2010 April;125(4): 654-9.Epub 2010 Mar 1.

Gross L. A broken trust: lessons from the vaccine-autism wars. PLoS Biol. 2009 May;7(5):1-7.

Madsen KM, Hviid A, Vestergaard M, Schendel D, Wohlfahrt J, Thorsen P, Olsen J, Melbye M. A Population-Based Study of Measles, Mumps and Rubella Vaccine and Autism. N Engl J Med. 2002 Nov 7;347(19):1477-82

Offit PA, Quarles J, Gerber MA, Hackett CJ, Marcuse EK, Kollman TR, Gellin BF, Landry S. Addressing parents’ concerns: do multiple vaccines overwhelm or weaken the infant’s immune system? Pediatrics. 2002 Jan;109(1):124-29.

Last updated 6/15/10