The US Influenza Vaccine Effectiveness (Flu VE) Network study sponsored by the Centers for Disease Control and Prevention (CDC) officially began its 14th season in Marshfield on December 26th. Center for Clinical Epidemiology & Population Health staff are actively recruiting patients presenting with cough, cold, or flu like symptoms from General Internal Medicine, Family Medicine, Pediatrics and Urgent Care at the Marshfield Center. Research coordinators work closely with clinicians and medical assistants to identify patients who may be eligible for the VE study. Nasal and throat swabs obtained from consenting patients are tested for flu by the Integrated Research and Development Laboratory (IRDL). The number of flu positives among those unvaccinated and vaccinated will be compared to estimate how well the vaccination is performing at preventing influenza in the population.
On February 15, 2018, CDC published the 2017-18 interim, or mid-season, estimate of influenza vaccine effectiveness (VE) based on enrollments at Marshfield Clinic and 4 other US sites. These estimates are used to guide next season vaccine strain selection, additional flu vaccine research and policy recommendations.
VE was 36% overall and statistically significant. This indicates that vaccination reduces the risk of influenza that requires outpatient medical attention by about one-third this season. A/H3N2 is the strain most commonly infecting people across the US this season. VE against A/H3N2 was 25%. VE was 67% against A/H1N1pdm09 and 42% against type B which are the two additional strains causing illnesses this season. The highest level of A/H3N2 protection (51%) was in children under 9 years of age. Although vaccine protection against A/H3N2 is low overall, vaccination can still prevent thousands of hospital admissions in the US during a severe season like this one.
Locally in Marshfield, over 1200 patients have been enrolled since late December and 479 (to date) are PCR positive for influenza; 84% of positives are A/H3N2, 9% are A/H1N1pdm09 and 5% are type B. Community support for the study continues to be high with a participation rate close to 80%.
There are over 30 MCRI staff members actively involved in the Flu VE study, including research coordinators, interviewers, programmers, laboratory associates and support staff. The lead investigators are Ed Belongia, MD and Huong McLean, PhD. Jennifer King, MPH serves as the Program Manager and Maddie Palmquist is the Lead Research Coordinator. Lynn Ivacic and Sherri Gusinski coordinate the laboratory activities.