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National Vaccine Advisory Committee

Report on 2009 H1N1 Vaccine Safety Risk Assessment

Approved by the National Vaccine Advisory Committee on January 20, 2010
Approved by the Assistant Secretary for Health on January 22, 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 five times 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 January 4, 2010, it has provided the following assessment for NVAC’s consideration on January 20, 2009, via telephone conference call. 

Report

Since our last report, an additional 35,085,900 doses of inactivated H1N1 and 7,191,600 doses of live attenuated H1N1 vaccine have been distributed.  A total of 74,714,720 doses of inactivated H1N1 and 19,435,300 doses of live attenuated H1N1 vaccine have been distributed as of 12/25/2009.  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.

The size of the population captured under active surveillance for vaccine safety is still limited and some analysis are based on small number of events.   As more data are available through active surveillance, conclusions will be based on a larger accumulation of data.  Larger samples may be needed to detect rare adverse events. Finally, the data collected and analyses conducted across systems are not uniform, making a consistent interpretation difficult.  Thus, the Working Group recommends that the Federal government continue to monitor H1N1 vaccine safety as more doses are administered and captured under active surveillance and thus 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

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

12/4/09

Adjudication and analysis of SAE

No SAE related to vaccine

Vaccine Adverse Event Reporting System (VAERS)

All health events

US Population

74,714,720b

19,435,300b

94,150,020b

12/25/09

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

556,749a

212,197a

768,946a

12/19/09

Rapid cycle analysis

No signal

Real-Time Immunization Monitoring System (RTIMS)

All health events

US Population

-

-

8,355a

12/29/09

Symptoms that trigger an alert

Cases being validated

Defense Medical Surveillance System (DMSS)

Pre-specified outcomes

1.4 million

456,892a

19,421a

476,313a

12/22/09

Rapid cycle analysis

No signal

Veteran’s Affairs (VA) Databases

  1. Enhanced VAERS
  2. Signal Detection

All health events

1.2 million

-

-

333,982b

12/28/09

Comparison of reports for H1N1 versus seasonal influenza vaccines

1 SAE confirmed after H1N1 immunization

Pre-specified outcomes

918,000

-

-

34,637a

12/28/09

Rapid cycle analysis

No signal

Centers for Mediare 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

120,127a

35,684a

161,138a

12/27/09

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

-

-

-

-

-

2 confirmed and probable cases 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