Photo Credit CDC PHIL
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The University of Rochester Medical Center has announced their plans to conduct a series of human trials of a live attenuated H7N9 vaccine delivered via a nasal spray (similar to Medimmune’s FluMist ®) over the coming months, and is actively enrolling (paid) volunteers.
Due to the use of a live-attenuated virus, recipients must agree to be isolated for 12 days following receipt of the vaccine to prevent inadvertent spread of the virus to others. While those risks are believed low, the CDC’s Q&A on LAIV (Live Attenuated Influenza Vaccines) states:
Can people receiving the nasal spray flu vaccine pass the vaccine viruses to others?
Yes, but its rare. Data indicate that both children and adults vaccinated with nasal spray can shed vaccine viruses after vaccination, although in lower amounts than occur typically with shedding of wild-type influenza viruses. Rarely, shed vaccine viruses can be transmitted from vaccine recipients to unvaccinated persons. However, serious illnesses have not been reported among unvaccinated persons who have been infected inadvertently with vaccine viruses.
See Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices – United States, 2013-14: Live Attenuated Influenza Vaccines: Shedding, Transmission, and Stability of Vaccine Viruses for more information.
If a virus is already circulating in a community – as with seasonal flu - then there is little harm in using a LAIV. But since H7N9 is not currently circulating in North America, anyone receiving the vaccine must be isolated as long as they are capable of shedding the virus, even if the risks of transmission are very low.
Forty-eight volunteers are being sought, with some receiving a live virus vaccine, followed several weeks later with an inactivated booster (thus requiring only one isolation period), and others receiving a live vaccine followed by a live booster (requiring two isolation periods).
My thanks to @makoto_au_japon for tweeting the link to this story via the University of Rochester Newsroom.
URMC Enrolling Subjects to Test H7N9 Pandemic Bird Flu Vaccines
October 14, 2013
URMC researchers are recruiting 48 participants for an isolation-style study testing live-virus bird flu vaccines later this fall.
The project will test two different schedules of nasal vaccine and boosters, hoping to shed light on which approach does a better job priming the immune system against H7N9, a new strain of bird flu identified in China in April this year.
“In a pandemic, time is of the essence,” said study investigator John Treanor, M.D., an internationally known flu expert who heads the University’s Vaccine Research Unit. “While no cases of H7N9 have yet been identified in the U.S., the Centers for Disease Control is following the situation closely and taking precautionary action, developing and testing a candidate vaccine in case it was ever needed.”
For the study, participants will be assigned to one of two groups. The first will receive intranasal vaccine (containing a live, weakened version of the H7N9 virus) and spend 12 days in a local isolation facility. Several weeks later, they would receive a booster shot of inactivated H7N9 in an outpatient setting.
The second group would follow a similar schedule, but would receive an additional dose of intranasal vaccine—requiring an additional 12-day isolation stay—just 28 days after the initial dose. Then, several weeks later, they also would receive a booster of live, inactivated H7N9 in an outpatient clinic.
Scientists in the lab will watch how strongly each of the two vaccine schedules triggers the production of protective proteins, called antibodies, in participants. Treanor and his team hope that the findings will shed light on whether one schedule or the other produces more favorable immune response—information that could guide CDC officials charged with shaping clinical recommendations in the face of a pandemic.
The research is funded by the National Institutes of Health, using experimental vaccines manufactured by MedImmune (makers of seasonal FluMist®) and Sanofi.
Currently, LAIV nasal spray vaccines are only approved for people who fall into specific categories. Again, from the CDC.
Who can be vaccinated with the nasal spray flu vaccine
The nasal spray is approved for use in healthy* people 2 through 49 years of age who are not pregnant.
Who should not be vaccinated with the nasal spray flu vaccine?
- Children younger than 2 years
- Adults 50 years and older
- People with a history of severe allergic reaction to any component of the vaccine or to a previous dose of any influenza vaccine
- People with asthma
- Children or adolescents on long-term aspirin treatment.
- Children and adults who have chronic pulmonary, cardiovascular (except isolated hypertension), renal, hepatic, neurologic/neuromuscular, hematologic, or metabolic disorders
- Children and adults who have immunosuppression (including immunosuppression caused by medications or by HIV)
- Pregnant women
Moderate or severe acute illness with or without fever is a general precaution for vaccination. GBS within 6 weeks following a previous dose of influenza vaccine is considered a precaution for use of influenza vaccines.
While we’ve not seen any reported human cases of H7N9 coming out of China in more than two months, influenza viruses have historically posed the greatest pandemic threat, and so no one is willing to ignore the possibility that this virus could re-emerge later this winter or in the spring (see FAO Warns On Bird Flu).
Which explains the ongoing multi-national pursuit of an effective H7N9 vaccine (see Taiwan Adjusts Their H7N9 Vaccine Production Outlook).
