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National Vaccine Advisory Committee

Report on 2009 H1N1 Vaccine Safety Risk Assessment

Approved by the National Vaccine Advisory Committee on March 23, 2010
Approved by the Assistant Secretary for Health on March 25, 2010

Background

The National Vaccine Advisory Committee (NVAC) established the H1N1 Vaccine Safety Risk Assessment Working Group (H1N1 VSRAWG) with the charge to conduct independent, rapid reviews of available safety monitoring data for the 2009 H1N1 influenza vaccines.  Since the Working Group was created, it has met nine times to review available data from the Federal vaccine safety monitoring systems listed in Table 1. Based on the review and discussion of H1N1 safety data available as of its meeting on March 8, 2010, it has provided the following assessment for NVAC’s consideration on March 23, 2010, via telephone conference call. 

Report

Since our last report, an additional 4,604,900 doses of inactivated H1N1 and 318,900 doses of live attenuated H1N1 vaccine have been distributed through the immunization program.  A total of 104,960,620 doses of inactivated H1N1 and 21,737,400 doses of live attenuated H1N1 vaccine have been distributed as of March 3, 2010. Most H1N1 vaccine safety monitoring systems report a substantial slowing of distribution and administration of H1N1 vaccine. However, since the last report, new data includes results from the PRISM system and data on pregnancy outcomes. 

Based on the data summarized in Table 1, the Working Group concluded that the data are adequate to assess the presence or absence of a signal.  Additionally, the Working Group concluded that the data do not favor a signal between the outcomes examined and the H1N1 vaccines. A signal is defined as an event that could be temporally occurring more often after vaccine receipt than anticipated by chance alone.  The evidence for this includes:

  1. No serious adverse events (SAE) have been attributed to the H1N1 vaccines in the clinical trials to date.
  2. Comparison of reporting in the Vaccine Adverse Event Reporting System (VAERS) of SAE after seasonal and other similar vaccines and H1N1 influenza vaccines generally show similar levels of SAE.
  3. For those systems conducting rapid cycle analysis1, the rates of adverse events for pre-specified outcomes are within expected values.
  4. Preliminary analyses on pregnancy outcomes have not detected a signal.

Since our last report, more H1N1 vaccine safety data has become available, and early results from the planned “end of season” analyses are emerging. As the pace of H1N1 vaccination in the population declines, the amount of new information being captured in each of the monitoring systems is decreasing. As a result, the Working Group will focus its efforts on reviewing new information and summarizing its experience for its final report. As a result, moving forward, the VSRAWG plans to meet on a monthly rather than bi-weekly basis. If a signal were to occur warranting the VSRAWG’s attention, the VSRAWG would resume its bi-weekly meeting schedule. The VSRAWG will continue to provide monthly reports to the NVAC and will provide a final report once sufficient data have accumulated.

Thus, the Working Group recommends that the Federal government continue to monitor H1N1 vaccine safety as the body of evidence accumulates on the safety profile of H1N1 vaccines.

All recommendations of the NVAC are made to the Department’s Assistant Secretary for Health.  The recommendation on vaccine safety monitoring listed above will be formally transmitted to the Assistant Secretary for Health, who will review and consider it for potential implementation options to include communications with various components of the Department.

H1N1 Vaccine Safety Risk Assessment Working Group Membership:

Stephen Cantrill, Associate Professor of Emergency Medicine, University of Colorado

Vicky Debold, Director of Research and Patient Safety, National Vaccine Information Center

Kathryn Edwards, Professor of Pediatrics, Vanderbilt University

Theodore Eickhoff, Professor Emeritus, University of Colorado School of Medicine

Susan Ellenberg, Professor of Biostatistics, University of Pennsylvania

Marie McCormick*, NVAC member, Professor of Maternal and Child Health, Harvard School of Public Health, former Chair of the IOM Immunization Safety Review Committee

Laura Riley, Assistant Professor of Obstetrics, Gynecology and Reproductive Biology, Massachusetts General Hospital

Mark Sawyer, Professor of Clinical Pediatrics, University of California, San Diego

*Chair of the NVAC H1N1 Vaccine Safety Risk Assessment Working Group

References

1.  Lieu TA, et al.  Real-time vaccine safety surveillance for the early detection of adverse events.  Med Care 2007; 45 (suppl2): S89-S95

 

Table 1: Number of Persons Exposed to H1N1 Vaccine in Monitoring Systems Reviewed by the H1N1 VSRAWG

Vaccine Safety Program

Outcomes Monitored

Population Monitored

H1N1 MIV1 Exposures Captured in System

H1N1 LAMV2 Exposures Captured in System

Total H1N1 Vaccine Exposures Captured in System

Current as of

Analyses

Results

H1N1 Vaccine Trials

All health events

10,852

10,352a

500a

10,852a

01/25/10

Adjudication and analysis of SAE

No SAE related to vaccine

Vaccine Adverse Event Reporting System (VAERS)

All health events

US Population

104,960,620b

21,737,400b

126,698,020b

03/03/2010

Comparison of reports for H1N1 versus seasonal influenza vaccines

SAE reporting after H1N1 are comparable to seasonal influenza immunization

Data-mining with comparison to similar vaccines

No signal

Vaccine Safety Datalink (VSD)

Pre-specified outcomes

9.5 million

1,212,853a

258,388a

1,471,241a

02/27/10

Rapid cycle analysis

No signal

Real-Time Immunization Monitoring System (RTIMS)

All health events

US Population

-

-

9,750a

02/25/10

Symptoms that trigger an alert

Cases being validated

Defense Medical Surveillance System (DMSS)

Pre-specified outcomes

1.4 million

1,153,858a

73,188a

1,227,046a

02/03/10

Rapid cycle analysis

No signal

Veteran’s Affairs (VA) Databases

1.Enhanced VAERS

 

2.Signal Detection

All health events

1.2 million

802,126b

 

-

802,126b

03/01/10

Comparison of reports for H1N1 versus seasonal influenza vaccines

No signal

Pre-specified outcomes

918,000

256,452a

-

256,452a

02/24/10

Rapid cycle analysis

No signal

Centers for Mediare and Medicaid Services (CMS)

Guillain-Barré syndrome

38 million

-

-

2,389,432a

03/02/10

Rapid cycle analysis

No signal

Indian Health Service (IHS)

Pre-specified outcomes

1.4 million

208,128a

51,856a

270,140

03/03/10

Rapid cycle analysis

No signal

Post-Licensure Rapid Immunization Monitoring System (PRISM)

Pre-specified outcomes

30 million (17 million registry enhanced)

1,841,762a

20,580a

1,862,342a

02/20/10

Rapid cycle analysis

No signal

Guillain-Barré syndrome (GBS) enhanced surveillance

Guillain-Barré syndrome

45 million

-

-

-

-

-

 

*Vaccines and Medications in Pregnancy Surveillance System (VAMPSS)

Maternal and fetal outcomes

3,100

-

-

-

-

-

-

1H1N1 monovalent inactivated vaccine

2H1N1 live attenuated monovalent vaccine

*Data not yet available

a Exposed to vaccine; b Doses of vaccine distributed

¥ Total is greater than sum of H1N1 MIV and LAMV as some H1N1 exposures are of unknown type