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National Vaccine Advisory Committee

Report on 2009 H1N1Vaccine Safety Risk Assessment

Approved by the National Vaccine Advisory Committee on December 16, 2009
Approved by the Assistant Secretary for Health on December 23, 2009

Background

The National Vaccine Advisory Committee (NVAC) established the H1N1 Vaccine Safety Risk Assessment Working Group (the Working Group) 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 twice to review available data from the Federal vaccine safety monitoring systems listed in Table 1. Based on the discussions of H1N1 safety data reviewed available as of its meeting on December 7, 2009, it provided the following assessment for NVAC’s consideration on December 16, 2009, via telephone conference call. 

Report

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.

It is still early in the H1N1 vaccination program and data on H1N1 vaccines’ safety are limited; as more H1N1 vaccines doses are administered these conclusions will be based on a larger accumulation of data.  Several of these analyses are based on small numbers of adverse events.  Larger samples may be needed to detect rare adverse events.  Finally, adverse events already reported are still being validated.  Thus, the Working Group recommends that the Federal government continue to monitor H1N1 vaccine safety as more doses are administered and 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.  Thus, 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

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

*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

12/4/09

Adjudication and analysis of SAE

No SAE related to vaccine

Vaccine Adverse Event Reporting System (VAERS)

All health events

US Population

39,628,820b

12,243,700b

51,872,520b

11/27/09

Comparison of reports for H1N1 versus seasonal influenza vaccines

SAE reporting after H1N1 are comparable to seasonal influenza immunization; GBS reporting is lower for H1N1 compared to seasonal

Data-mining with comparison to similar vaccines

No signal

 Vaccine Safety Datalink (VSD)

Pre-specified outcomes

9.5 million

353,204a

173,149a

526,353a

11/29/09

Rapid cycle analysis

No signal

Real-Time Immunization Monitoring System (RTIMS)

All health events

US Population

-

-

4,311a

11/30/09

Symptoms that trigger an alert

Cases being validated

Defense Medical Surveillance System (DMSS)

Pre-specified outcomes

1.4 million

217,811a

7,378a

225,189a

11/28/09

Rapid cycle analysis

No signal

Veteran’s Affairs (VA) Databases

  1. Enhanced VAERS
  2. Signal Detection

All health events

1.2 million

-

-

268,076b

11/30/09

Comparison of reports for H1N1 versus seasonal influenza vaccines

No SAE reported after H1N1 immunization

Pre-specified outcomes

918,000

13,731a

N/A

13,731a

11/30/09

Rapid cycle analysis

No signal

Centers for Medicare and Medicaid Services (CMS)

Guillain-Barré syndrome

38 million

-

-

193,107a

12/2/09

Rapid cycle analysis

No signal

Indian Health Service (IHS)

Pre-specified outcomes

1.4 million

63,643a

20,847a

84,490a

12/1/09

Rapid cycle analysis

No signal

*Post-Licensure Rapid Immunization Monitoring System (PRISM)

Pre-specified outcomes

30 million (17 million registry enhanced)

-

-

-

-

Rapid cycle analysis

-

Guillain-Barré syndrome (GBS) enhanced surveillance

Guillain-Barré syndrome

45 million

-

-

-

-

-

No cases of GBS following H1N1 vaccination

*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

aExposed to vaccine; bDoses of vaccine distributed