Breaking News
March 19, 2018 - Telediabetes program improves blood sugar control for veterans
March 19, 2018 - Morning Break: House Nixes ‘Right-to-Try’ Bill; Purdue’s PR Makeover; Air in the Brain
March 19, 2018 - Heart researchers develop a new, promising imaging technique for cardiac arrhythmias
March 19, 2018 - Mice study shows how BPA exposure during pregnancy can lead to altered brain development
March 19, 2018 - Breastfeeding mothers who overeat may increase risk of health problems in offspring
March 19, 2018 - New mobile application can detect atrial fibrillation that causes strokes
March 19, 2018 - Study finds low rates of preconception counseling among women of childbearing age with diabetes
March 19, 2018 - ObsEva SA Reports Positive Topline Results from IMPLANT2 Phase 3 Clinical Trial of Nolasiban in IVF
March 19, 2018 - D.C. Week: States Plead for Federal $$ in Opioid Fight
March 19, 2018 - Polycystic ovary syndrome – Genetics Home Reference
March 19, 2018 - Reducing co-payments improves patient, physician adherence to guideline-recommended treatment post-MI
March 19, 2018 - Normalizing estrogen levels can benefit female athletes with irregular menstrual periods
March 19, 2018 - Fitness trackers and virtual coaches motivate patients to exercise post cardiac rehab
March 19, 2018 - Atrial fibrillation patients could reduce risk of dementia by taking stroke prevention drugs
March 19, 2018 - Low sperm count more prevalent with other health problems finds study
March 19, 2018 - Male birth control pill taken once a day shows success
March 19, 2018 - AcelRx Announces Receipt of Type A FDA Meeting Minutes and Plans to Resubmit the DSUVIA New Drug Application in Q2 2018
March 19, 2018 - Eye Docs Adopt EHRs Despite Reservations
March 19, 2018 - CRISPR enhances cancer immunotherapy
March 19, 2018 - Study finds first evidence of delayed aging among Americans
March 19, 2018 - Aussies unaware of sun protection rules to prevent skin cancer
March 19, 2018 - Essential oils linked to abnormal breast development in boys
March 19, 2018 - ‘Tummy Tuck’ Relieved Postpartum Back Pain/Incontinence
March 19, 2018 - New biomarkers for neuroblastoma, a type of cancer in children
March 19, 2018 - Hookah Smoking Carries a Poisoning Risk
March 19, 2018 - Do Mood and Anxiety Affect MS Disability?
March 19, 2018 - Mean depth of ultrasonographic penetration greater in autism
March 19, 2018 - Platypus milk may help combat antibiotic resistance
March 19, 2018 - U.S. IDE study of THERMOCOOL SMARTTOUCH SF Catheter completes patient enrollment
March 18, 2018 - E-cigarette use exposes adolescents to potentially cancer-causing chemicals
March 18, 2018 - GOP Senator: Solve Opioid Crisis Through Community, Not Policy
March 18, 2018 - Why is ADHD more common in boys than girls?
March 18, 2018 - Measles alert after two passengers with the disease fly into US
March 18, 2018 - FDA looks to remove nicotine from cigarettes
March 18, 2018 - FDA moves to cut nicotine in cigarettes, helping smokers kick habit
March 18, 2018 - Athenex Announces Phase II Clinical Study Results for KX2-391 Ointment for the Treatment of Actinic Keratosis
March 18, 2018 - Surgery Tied to Better Outcomes in Kids with T2D
March 18, 2018 - Scientists use nanotechnology to detect molecular biomarker for osteoarthritis
March 18, 2018 - Research establishes use of chimeric cells as potential therapy for Duchenne muscular dystrophy
March 18, 2018 - Researcher working to develop improved endoscopic probe for colonoscopies
March 18, 2018 - Researchers develop way to sequence entire fetal genome by modifying prenatal testing method
March 18, 2018 - FDA Approves PDUFA Fee Waiver for Gimoti New Drug Application
March 18, 2018 - P2Y12 Tx Subsidy Yields Positive Response from Docs, Patients
March 18, 2018 - Are Proteins in Formula Linked to Type 1 Diabetes?
March 18, 2018 - Exercise does not seem to increase bone marrow edema in healthy people
March 18, 2018 - Researchers delineate architecture of nuclear pore complex in yeast cells
March 18, 2018 - ‘It’s Just Ghetto-izing People’: What We Heard This Week
March 18, 2018 - Alzheimer’s disease: Neuronal loss very limited
March 18, 2018 - Study reveals impact of intense, changing work schedules experienced by medical interns
March 18, 2018 - Jobs That Keep the Mind Sharp … Even Into Retirement
March 18, 2018 - Facial Scarring Improved with Botulinum Toxin
March 18, 2018 - Data detectives shift suspicions in Alzheimer’s to inside villain
March 18, 2018 - Shorter Preventive TB Tx Effective for HIV+ Patients
March 18, 2018 - New technique for identifying alcoholism puts treatment options at patients’ and providers’ fingertips
March 18, 2018 - Researchers uncover four microRNAs as potential biomarkers for atrial fibrillation
March 18, 2018 - IRX Therapeutics Announces Initiation of Phase 2 Clinical Trial of IRX-2 in Squamous Cervical or Vulvar Intraepithelial Neoplasia 3
March 18, 2018 - OncoBreak: Learning from Silence; ‘Rigged’ Drug System; NCCN Guidelines Questioned
March 18, 2018 - The coffee cannabis connection
March 18, 2018 - Novel centrifugal-flow pump for heart failure patients provides improved long-term outcomes
March 18, 2018 - U.S. FDA Accepts New Drug Application for Prucalopride (SHP555) for Chronic Idiopathic Constipation
March 18, 2018 - Cath Lab Recap: iFR vs FFR $$; Ridaforolimus-Eluting Stent
March 18, 2018 - Tree care workers need better training to handle dangers on the job, study finds
March 18, 2018 - Dementia patients do not undergo diagnostic evaluation at onset of disease, study finds
March 18, 2018 - Transplanting enhanced interneurons restores brain rhythms in mouse model of Alzheimer’s
March 18, 2018 - Gene Therapy Flops for Critical Limb Ischemia
March 17, 2018 - Study spotlights risks in anesthesiologist handoffs
March 17, 2018 - Verb fluency test may be useful tool for differential diagnosis of cognitive failure
March 17, 2018 - Health Tip: Suggestions to Improve Your Cholesterol
March 17, 2018 - Fructans Suspect in Non-Celiac Gluten Sensitivity
March 17, 2018 - Aspirin therapy appears safe before thyroid surgery
March 17, 2018 - Minimally invasive surgical device may one day provide lasting heart repair
March 17, 2018 - UIH and RaySearch enter into new partnership
March 17, 2018 - Is BMI Too Inexact? | Medpage Today
March 17, 2018 - Sleep apnea study finds male-female differences in cerebral cortex thickness, symptoms
March 17, 2018 - Leicester research could help identify people with asthma of different severities
March 17, 2018 - Biosense Webster enrolls and treats first AF patient in clinical study of new RF balloon catheter
March 17, 2018 - Participants in rogue herpes vaccine research take legal action
March 17, 2018 - Imara Doses First Patient in Phase 2a Clinical Trial of IMR-687 for Sickle Cell Disease
March 17, 2018 - AAP: Prevent Medication Errors by Improving Processes
March 17, 2018 - Severe sleep apnea during REM sleep tied to acute CV events
Flu Vax Efficacy 25% Against Predominant H3N2 Strain So Far

Flu Vax Efficacy 25% Against Predominant H3N2 Strain So Far

image_pdfDownload PDFimage_print

Action Points

  • Influenza A (H3N2) comprised about 70% of influenza infections this year, and interim vaccine efficacy against this strain was only 25%, according to the CDC.
  • Note that influenza activity began to increase in early November and rose sharply from December through February, with some of the highest levels of influenza-like illness and hospitalization rates in recent years.

Influenza A (H3N2) comprised about 70% of influenza infections this year, and interim vaccine efficacy against this strain was only 25%, CDC researchers said.

Individual vaccine efficacy ranged from 25% (95% CI 13%-36%) against influenza A (H3N2) to 42% (95% CI 25%-56%) against influenza B viruses to 67% (95% CI 54%-76%) against influenza A (H1N1)pdm09 viruses, reported Brendan Flannery, PhD, lead investigator for the CDC’s U.S. Flu Vaccine Effectiveness Network, and colleagues.

Overall vaccine efficacy against influenza A and B associated with medically attended acute respiratory illness was 36% (95% CI 27%-44%), the team wrote in the Morbidity and Mortality Weekly Report.

However, the 25% efficacy against H3N2 strains is higher than earlier estimates suggesting effectiveness as low as 10%.

Asked for his perspective, Peter Hotez, MD, PhD, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, who was not involved with the research, highlighted two important figures: that only 26% of pediatric flu deaths occurred in vaccinated children, and that the risk for “medically attenuated” influenza illness was reduced by more than 59% among vaccinated children.

“These results confirm my earlier concerns that public health messaging this year was too focused on the low efficacy of the vaccine in preventing flu infection, rather than preventing flu deaths,” he told MedPage Today. “This message was sadly encouraged by the antivaxxer community. The public health community … in general [was] not sufficiently visible in the media about the importance of getting vaccinated.”

William Schaffner, MD, of Vanderbilt University School of Medicine in Nashville, added that vaccine effectiveness estimates relate to completely preventing infection, but that is not the whole story: “One of the main reasons we use influenza vaccine is to prevent complications, and that’s never measured except in research studies that come later, but they always show that vaccinated people have lower rates of pneumonia hospitalization and dying,” he told MedPage Today.

Schaffner added that the vaccine, while imperfect, “can prevent a lot of infections and modulate many others, and this is a very serious illness, so I’ll take every ounce of prevention I can get.”

Flannery and colleagues wrote that despite “ongoing challenges” with the H3N2 component since the 2011-2012 season, vaccine efficacy was higher in the U.S. for this strain than it was in Australia (10%) and Canada (17%). The U.S. rate was “similar” to the final vaccine efficacy numbers for the 2016-2017 season for this strain, the researchers said.

They emphasized that there is no “definitive evidence” of antigenic drift of viruses circulating this season compared with those included in the vaccine. In addition, egg-based vaccines may be partially responsible for a less effective vaccine against H3N2, but additional studies are needed to assess whether vaccine efficacy varies by vaccine type.

The researchers derived this data from 4,562 children and adults with acute respiratory infection enrolled in five study sites. There were 38% that tested positive for influenza, including 81% that tested positive for influenza A. Among the 1,340 influenza A viruses, 85% were H3N2, and 98% of B viruses were B/Yamagata. The portion of patients vaccinated ranged from 45% to 59% among study sites. Among these participants, 43% of those testing positive for influenza received the 2017-2018 seasonal influenza vaccine versus 53% of influenza-negative participants, the authors said.

There was statistically significant protection against “medically attenuated” influenza among children ages 6 months to 8 years, and among adults 18-49 (VE=33%, 95% CI 16%-47%), but no statistically significant protection among other age groups.

‘Wake Up Call’ for Better Vaccine Development

Stephen Morse, PhD, director of the Infectious Disease Epidemiology Certificate Program of Columbia University Mailman School of Public Health in New York City, told MedPage Today that the only surprising thing about this data was how unsurprising it was. He said he hoped it was “a ‘tipping point’ that will finally galvanize some long-needed improvements in how we produce this vaccine.”

Specifically, Morse noted the strong case for applying these newer and more rapidly adaptable technologies to influenza vaccines, which need to be changed every few years.

“Some vaccines have been produced by modern biotechnology, making just the proteins we need for the vaccine,” he said. “We should bring influenza vaccine production up to date. We can hope that the bad news about lower vaccine effectiveness this year will add momentum to these efforts.”

Schaffner cautioned that although a number of manufacturers are creating their own version of a better vaccine, “waiting for perfection is the enemy of the current good.

“We have more research ongoing to make a better influenza vaccine than we’ve had in the previous 40 years put together. My optimism is that based on reasonable expectations, in 5 to 8 years, we’re going to have more and different influenza vaccines.”

Hotez agreed that investments should be expanded in technologies for both H3N2 and universal flu vaccines, “but even this current vaccine was still effective at preventing deaths from H3N2.”

Flu Was Early and Widespread

A related second report in MMWR, by Alicia P. Budd, MPH, of the CDC, and colleagues, noted that influenza activity began to increase in early November and “rose sharply” from December through February, with “some of the highest levels of influenza-like illness and hospitalization rates in recent years.”

Adults age 65 and older accounted for almost 60% of documented influenza-associated hospitalizations. Among all hospitalizations, over 86% were associated with influenza A, and among patients where subtype was available, over 86% of those were associated with influenza A (H3N2).

Among hospitalized adults for whom information on underlying medical conditions was available, over two-thirds had “at least one medical condition placing them at high risk for influenza-related complications,” with the most common being cardiovascular disease (35.5%). Among hospitalized children with such information, about half had at least one underlying medical condition, with the most common being asthma (22.8%).

The mean age of children who died of influenza-associated causes was 7.4. Among those children with a known medical history, 54% had at least one underlying medical condition that placed them at increased risk of influenza complications. There were 54 children eligible for influenza vaccination, but only 14 had received at least one dose of the vaccine before illness onset.

Morse said that every new development in influenza “makes us painfully aware of how little we really know about this familiar and mundane virus. Better understanding can only help to develop more effective vaccines. The long-standing debates about the effect of repeated immunizations, and how to improve the immune response, show that there is still much we don’t understand about the immunology of influenza infection and how our immune systems respond to the virus.”

Flannery and colleagues disclosed no conflicts of interest.

Budd and colleagues disclosed no conflicts of interest.


Tagged with:

About author

Related Articles