During a CDC teleconference Jan. 12 on the current flu epidemic,(www.cdc.gov) CDC Director Brenda Fitzgerald, M.D., said the United States is currently experiencing widespread and intense influenza activity.
So far this season, Fitzgerald said influenza A (H3N2) has been the predominant strain circulating, with this virus often being linked to severe illness that targets children and patients 65 and older, in particular. During flu seasons dominated by H3N2, there typically are more hospitalizations and deaths than in other years.
"While our surveillance systems show that nationally, the flu season may be peaking now, we know from past experience that it will take many more weeks for flu activity to truly slow down," she said.
Fitzgerald also said the CDC continues to recommend the flu vaccine, even though historical data from Australia and the United States show the vaccine hasn't been very effective against H3N2.
Later in the call, Dan Jernigan, M.D., M.P.H., director of the Influenza Division in the CDC's National Center for Immunization and Respiratory Diseases, said the agency estimates the flu vaccine's specific effectiveness against H3N2 to be in the low-30s percentage range.
- So far this flu season, the influenza A (H3N2) strain has been predominant, with this particular virus often being linked to severe illness that targets children and patients 65 and older, in particular.
- Dan Jernigan, M.D., M.P.H., director of the Influenza Division in the CDC's National Center for Immunization and Respiratory Diseases, said the CDC estimates the flu vaccine's specific effectiveness against H3N2 to be in the low-30s percentage range.
- A perspective article published online Nov. 29, 2017, by the New England Journal of Medicine made the case for developing a universal influenza vaccine "that will protect against seasonal influenza drift variants as well as potential pandemic strains, with better durability than current annual vaccines."
"While our flu vaccines are far from perfect, they are the best way to prevent getting sick from the flu, and it is not too late to get one," Fitzgerald said. "As of this last month, manufacturers reported that they have shipped more than 151 million doses of flu vaccines, so it should be readily available."
Jernigan covered additional details, including geographic locations of illness, what physicians are reporting and the severity of illness being seen.
"First … I think the simplest way to describe it is that flu is everywhere in the U.S. right now," Jernigan said. "There's lots of flu in lots of places. Our team that does this kind of surveillance studies has been doing this particular thing for 13 years, and this is the first year we had the entire continental U.S. be the same color on the graph -- meaning there's widespread activity in all of the continental U.S. at this point."
Jernigan agreed that the flu season appears to be peaking now and mirrors activity from the 2014-15 and 2012-13 seasons, both of which had H3N2 as the predominant strain. He said this flu season seems to be tracking somewhat worse than the 2012-13 season and probably better than 2014-15.
Flu Shot OK for Patients With Egg Allergies
A guideline published recently in the Annals of Allergy, Asthma and Immunology(www.annallergy.org) built on recent guidance from the CDC's Advisory Committee on Immunization Practices, saying that physicians don't need to ask patients if they have an egg allergy before administering flu vaccine.
Additionally, the guideline said patients with egg allergies no longer need to see an allergist before getting a flu shot, and they do not need to be observed by medical staff after vaccine administration any longer than a patient without this allergy.
Jernigan referenced the CDC's FluView weekly influenza surveillance report,(www.cdc.gov) saying hospitalizations associated with influenza had almost doubled from the previous week.
"If you were to look at who is being hospitalized, clearly, the highest rates are among those that are over age 65, and even for those that are age 50-64, in that sort of baby boomer generation," he said. "They are seeing high numbers, and they are increasing over last week.
"The other area that we are, of course, following closely is (hospitalizations of) children younger than age 5, which have also increased or almost doubled in the last week."
Additionally, seven flu-associated pediatric deaths were reported during the week ending Jan. 6, bringing the total reported to the CDC for this flu season to 20.
Vaccine Science Fellows' Perspective
The two current AAFP Vaccine Science Fellows offered some perspective on this year's flu epidemic and vaccine.
Amra Resic, M.D., of Palm Harbor, Fla., told AAFP News she would advise family physicians to continue to discuss the importance of vaccinations in general with their patients, including that of the seasonal flu vaccine.
"Regardless of the annual effectiveness of the flu vaccine, if vaccination can help avert disease (and especially death) in one patient -- it's worth it," she said. "As physicians, we took an oath to 'prevent disease whenever we can, for prevention is preferable to cure,' and vaccines are a great example of this."
Resic also reminded her colleagues that for the second season in a row, the CDC's Advisory Committee on Immunization Practices recommended against use of the live attenuated influenza vaccine (LAIV, FluMist) because of the vaccine's reduced efficacy.
Kimberly Stump, M.D., of Corpus Christi, Texas, told AAFP News she's seen a spike in influenza in her area, as well as in flu-like illnesses that aren't testing positive for influenza.
"That's always frustrating for both doctors and patients," she said. "What I've seen doesn't seem out of range for the normal ebb and flow of flu through the years."
Stump added that from what she's observed, the flu vaccine hasn't been very effective against the illness this season.
However, she advises family physicians to not get complacent.
"It's always hard to stay vigilant about chronic risks, and flu is always a risk," Stump said. "Everyone wants a better vaccine, but this is what we have now, and it does help. Let's use it. Flu still kills people -- even healthy young people."
Stump said family physicians should be extra cautious about protecting patients against the flu, including not only the elderly and infants, but also people with lung problems or decreased immune function and pregnant women.
"I try to encourage anyone who has contact with friends or family in these groups to get the vaccine to help protect their loved ones; that's pretty much everyone," she said.
Call for Universal Influenza Vaccine
A perspective article published online Nov. 29, 2017, by the New England Journal of Medicine(www.nejm.org) made the case for developing a universal influenza vaccine "that will protect against seasonal influenza drift variants as well as potential pandemic strains, with better durability than current annual vaccines."
"Among other advantages, in all likelihood, such a vaccine would not be subject to the limitations of egg-based vaccine technology," the authors said.
Fitzgerald echoed this sentiment during the recent teleconference, saying the agency hopes that someday, a universal flu vaccine will be available to attack all influenza-type viruses and provide protection that lasts for years.
"But until that day arrives, we will continue to improve the vaccines that we have and find ways and tools to help Americans reduce their risk of getting sick," she concluded.
Related AAFP News Coverage
CDC: 2017-18 Flu Season in U.S. Dominated by H3N2 Viruses
Vaccine Effectiveness Uncertain Based on Australian Data
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