BETHESDA, MD 08 August 2013—Tim R. Brown, director of clinical pharmacotherapy at the Center for Family Medicine at Akron General Medical Center, said this year's decision to purchase quadrivalent vaccines was influenced by the severity of the 2012–13 flu season.
"Since last year was such a horrific season, we're looking at . . . how to make sure we don't have a repeat in 2013–14," Brown said. "So we're using quadrivalent across the board for all of our folks."
The state of Ohio reported 5236 influenza-related hospitalizations and four flu-related pediatric deaths through mid-May of the 2012–13 influenza season. State surveillance data indicate that the 2012–13 season was more severe than other recent flu seasons, excluding 2009–10, when the influenza H1N1 pandemic occurred.
The Centers for Disease Control and Prevention (CDC) said the past flu season was "early and intense" throughout much of the United States and of moderate severity overall.
Brown attributed much of last season's illness in Ohio to a mismatch between the influenza type B strain in the vaccines and the type B viruses circulating in the community.
"A lot of our older folks last year . . . had the strain that wasn't covered," Brown said. He said caring for these patients "pushed our service to the limit" and led to an increase in hospitalizations for influenza.
Less than 40% of the influenza type B viruses isolated from Ohio patients and genetically characterized matched the strain in the trivalent vaccines, according to state data.
Historically, the influenza type B strain chosen for the vaccine each season is a mismatch for circulating viruses about half the time. To overcome this problem, manufacturers recently began producing quadrivalent influenza vaccines that contain two type A and two type B strains.
Three quadrivalent vaccine products are licensed for the upcoming flu season.
Brown said quadrivalent vaccines are so new that their effectiveness can't be definitively assessed yet, but having an extra B strain ought to be beneficial. And he said that having just one formulation on hand for use in all patients age 6 months and up eliminates the possibility of inadvertently administering the wrong flu vaccine to someone.
CDC hasn't given preference for one vaccine type over any other when the products are used in accordance with their labeling.
Jeffrey Bratberg, clinical associate professor of pharmacy practice at the University of Rhode Island College of Pharmacy in Kingston and infectious diseases specialist at the Roger Williams Medical Center in Providence, expects to use quadrivalent vaccines in adult patients this fall.
That decision is influenced by state policy. Rhode Island, through its universal vaccine purchasing program, buys influenza vaccines for use throughout the state.
Registered health care providers and facilities receive the vaccines at no cost, and patients are not charged for vaccination. Medicare and Medicaid beneficiaries are not eligible for the program.
For the 2013–14 flu season, the state has purchased MedImmune's FluMist Quadrivalent for patients age 2–18 years and GlaxoSmithKline's Fluarix Quadrivalent for people age 3 years or older. Pediatric-sized doses of Sanofi Pasteur's Fluzone Trivalent will be available from the state for children age 6–35 months, Bratberg said.
Louis Sokos, assistant director of pharmacy at West Virginia University (WVU) Hospitals in Morgantown, is responsible for purchasing influenza vaccines for the hospital and, since last year, several of its provider-based clinics.
Sokos said the hospital's infectious diseases pharmacists and physicians debated for a couple of weeks about whether to purchase trivalent or quadrivalent vaccines this year.
"It was kind of a mixed bag on what folks thought was necessary, because there were no different recommendations from the CDC for the trivalent versus quadrivalent," Sokos said.
Ultimately, Sokos said, he prebooked quadrivalent and trivalent vaccines from GlaxoSmithKline, with the majority of the doses being the quadrivalent formulation. A smaller purchase of MedImmune's quadrivalent FluMist vaccine was ordered for pediatric clinics, he said.
Since then, he said, the hospital considered switching some of its order for GlaxoSmithKline's quadrivalent vaccine to the trivalent formulation, which costs less. But he was told that trivalent vaccine was no longer available to order.
GlaxoSmithKline vaccines spokesman Robert Perry said the company's influenza vaccine stocks have already been allocated to customers, and the production of additional trivalent flu vaccine for this season is unlikely.
Perry said the German facility that manufactures trivalent influenza vaccine is instead making Pediarix, the company's diphtheria–tetanus toxoids–acellular pertussis–hepatitis B–poliovirus combination product, to alleviate a U.S. shortage of Sanofi Pasteur's similar pentavalent vaccine.
Perry said his company has been pleasantly surprised by clinicians' rapid acceptance of quadrivalent flu vaccines, and he expects the marketplace to shift toward those products.
Other options for flu vaccine purchasers are also available now.
Sokos said WVU clinicians made limited use last season of Sanofi Pasteur's trivalent Fluzone intradermal vaccine, which was licensed in 2011. He said this was the only flu vaccine available late last season when he needed to order additional doses.
"The nurses seemed to like that," he said. "It's not a real difference from the patients' perspective, from what I understand."
Sokos said he mentioned the intradermal vaccine and Flublok, Protein Science Corp.'s new recombinant vaccine, during discussions of what to buy for this flu season. He said the infectious diseases specialists "weren't overly excited one way or another" about those products.
Flublok is the only U.S.-licensed seasonal influenza vaccine that contains no egg proteins. The currently marketed version is trivalent, and company officials have stated that a quadrivalent version is in development.
CDC advisers in June unanimously recommended the use of Flublok in adults 18–49 years of age who are severely allergic to eggs, but at presstime, CDC had not officially endorsed that recommendation.
Bratberg noted that CDC has relaxed its recommendations about influenza vaccination in patients who report an allergy to egg proteins.
According to an algorithm that CDC released last August, people who can safely eat lightly cooked eggs, like scrambled eggs, should receive influenza vaccine under the same protocol as patients with no reported egg allergy.
People whose only allergy symptom is hives after eating eggs or egg-containing products should be administered trivalent vaccine and observed for 30 minutes, according to CDC.
Brown said that for the upcoming flu season, his family medicine practice considered Flublok but ultimately placed greater weight on the protection expected from the quadrivalent vaccine.
"We've not had that big of an issue with egg allergy in our practice setting," Brown said.
Bratberg likewise said he's not too concerned that Rhode Island won't provide Flublok for the "very small percentage of people" with serious egg allergies.
For patients who do get influenza, the early use of antivirals remains a mainstay of therapy.
Bratberg said he expects oseltamivir to be largely effective against circulating strains of influenza type A, but he's also looking forward to the approval of newer agents that are now in clinical studies.
He urged pharmacists to engage in collaborative practice agreements that allow them to dispense oseltamivir to patients who come to the pharmacy with early symptoms of influenza. But he said vaccinating patients against influenza is the number-one thing pharmacists can do to keep patients healthy during the flu season.