Journal Reviews

Live influenza vaccine reactions rare

No reports of HCWs infecting patients

Izurieta HS, Haber P, Wise RP, et al. Adverse Events Reported Following Live, Cold-Adapted, Intranasal Influenza Vaccine. JAMA. 2005; 294:2720-2725.

Reports to the federal vaccine adverse event reporting system (VAERS) in the first two seasons of trivalent live, attenuated influenza vaccine (LAIV-T) use did not identify any unexpected serious risks with the vaccine when used according to approved indications, the authors report. However, some secondary transmission did occur with the live vaccine, though none of it involving the much-discussed scenario of a vaccinated health care worker infecting an immune-compromised patient. "There were 22 reports of possible secondary transmission of the vaccine virus from vaccinees to nonvaccinees," the authors report. "None of the events resulted in hospitalization."

Among 18 cases in which age was reported, ages ranged from 3 to 64 years. Among 17 reports for which this information was available, the interval from exposure to a vaccinated person to symptom onset ranged from a few hours to 15 days. Thirteen of the events (59%) involved transmission to a health care clinician who administered the vaccine. Of them, six events reportedly occurred among military medical personnel exposed to vaccinees who already had respiratory symptoms at the time of LAIV-T vaccination.

One possible secondary transmission event reported as serious concerned a 3-year-old girl with influenza-like symptoms followed by lobar pneumonia three days after her mother received LAIV-T. Only one report of suspected secondary transmission included laboratory analysis to distinguish between vaccine and wild-type strains. Fifteen days after a pediatrician received LAIV-T, her 4-year-old child developed influenza-like symptoms. The Centers for Disease Control and Prevention influenza laboratory analysis revealed that the child’s isolate was wild-type influenza A(H3N2) similar to A(H3N2) viruses that had been circulating and did not contain any gene of the vaccine strain. There was no report of possible secondary transmission to an immunosuppressed individual.

"Secondary transmission of the vaccine virus merits further investigation," the authors conclude. "Reports of asthma exacerbations in vaccinees with prior asthma history highlight the risks of vaccine use inconsistent with approved labeling."

In June 2003, the Food and Drug Administration licensed LAIV-T for intranasal administration to healthy persons 5 to 49 years of age. Although prelicensure testing involved 20,228 vaccinees, clinical trials were not of sufficient size to detect rare adverse events reliably.

To identify adverse events reported following LAIV-T administration after licensure, the researchers looked at all adverse events reported to VAERS during the 2003-2004 and the 2004-2005 influenza seasons. Approximately 2.5 million people received LAIV-T during the first two post-licensure flu seasons. As of Aug. 16, 2005, VAERS received 460 adverse event reports for vaccinations received from August 2003 through July 2005. No fatalities were reported. There were seven reports of possible anaphylaxis, two reports of Guillain-Barré syndrome, one report of Bell’s palsy, and eight reports of asthma exacerbation among individuals with a prior asthma history. Events in individuals for whom the vaccine was not indicated accounted for 73 reports (16%).

It’s past time to fight HIV like any other epidemic

Deaths down, but infections continue

Frieden TR, Das-Douglas M, Kellerman SE, et al. Applying Public Health Principles to the HIV Epidemic. New Eng Jrl Med2005; 353:2397-2402.

Although HIV infection has killed more than half a million people in the United States, a comprehensive public health approach that has stopped other epidemics has not been used to address this one, the authors emphasize.

"When HIV infection first emerged among stigmatized populations (homosexual men, injection-drug users, and immigrants from developing countries), the discriminatory responses ranged from descriptions of AIDS as retribution’ to violence and proposals for quarantine, universal mandatory testing, and even tattooing of infected persons," they charge.

This response led to "HIV exceptionalism," an approach that advocated both for special resources and increased funding and against the application of standard methods of disease control. The need for extra resources remains essential, but the failure to apply standard disease-control methods undermines society’s ability and responsibility to control the epidemic. Now, given the availability of drugs that can effectively treat HIV infection and progress on antidiscrimination initiatives, perhaps society is ready to adopt traditional disease-control principles and proven interventions that can identify infected persons, interrupt transmission, ensure treatment and case management, and monitor infection and control efforts throughout the population, they note.

"Doing so will have political and economic costs," the authors state. "The political costs include offending both sides of the political establishment: conservatives who oppose the implementation of effective prevention programs, including syringe exchange and the widespread availability of condoms, and some HIV activists who oppose expansion of testing, notification of the partners of infected persons and what some see as inappropriate medicalization’ of the response to the epidemic."

Researchers have identified the virus, established diagnostic tests, and created effective drugs and care systems that have reduced the number of deaths from AIDS in the United States by 70% since 1995. "However, 25 years into the epidemic, progress is stalled," they argue. Indeed, the number of deaths among people with AIDS has not declined since 1998, and the number of newly diagnosed cases is rising slightly. Disease transmission continues at the same or, possibly, a slightly higher rate. High-risk behavior remains common and is increasing in some groups. Late diagnosis of infection is common and notification of the partners of infected persons is rare, they stress.

Proven interventions, such as the use of condoms, clean needles, expanded voluntary screening, and linkage to care, could prevent most HIV infections. Improving community-based efforts and counseling of individual patients to prevent transmission, supporting patients to facilitate their return to care, and improving the availability of effective treatment could further reduce transmission. "We do not consistently apply these proven strategies," they lament.

Using the current CDC estimate of 40,000 new HIV infections per year, the potential to prevent half to two-thirds of these infections, and the current average lifetime cost of care for a patient with HIV infection of $200,000, more effective epidemic control would save between $4 billion and $5.4 billion per year. "If we fully apply public health principles to the HIV epidemic, we can improve the health of people living with HIV infection and prevent tens of thousands of people in this country from becoming infected with HIV in the next decade," they conclude.