Cell-based flu vaccine 36% more effective than egg-based vaccine

Seqirus released adjusted data showing that its cell-based quadrivalent influenza vaccine was around 36% more effective than the standard egg-based quadrivalent vaccine in preventing influenza-like symptoms in people aged 4 years and older during the most recent influenza season in the United States.

“In other words, people who were vaccinated with [the quadrivalent, inactive, cell-based influenza vaccine (QIVc)] were 36% less likely to present to a primary care setting with influenza-like illness in the 2017-2018 flu season.” Gregg Sylvester, MD, MPH, Seqirus global head of medical affairs, told Infectious Disease News.

Last influenza season was one of the worst in recent years, causing an estimated 80,000 deaths and 900,000 hospitalizations, according to the National Foundation for Infectious Diseases. The predominant circulating strain was influenza A(H3N2), which is known for evading the seasonal vaccine and causing relatively severe illness. Seqirus noted that research has shown some H3N2 viruses mutate when they are grown in eggs, leading to reduced vaccine effectiveness. The CDC estimated adjusted overall vaccine effectiveness last season to be 40%.

“When produced completely outside of the egg-based process, cell-based influenza vaccines avoid egg-adapted changes, which means they may offer a closer match and potentially improved protection compared to standard egg-based options in some seasons,” the company said.

Findings from a Seqirus-commissioned study were presented at the NFID 2018 Clinical Vaccinology Course. Researchers used data from Aug. 1, 2017, to March 31, 2018, from one of the largest EMR providers for primary care practices in the U.S. to estimate the relative vaccine effectives (rVE) of QIVc compared with an egg-based quadrivalent, inactive influence vaccine (QIVe).

They analyzed the records of 92,192 patients who received QIVc (median age, 59 years) and 1,255,983 patients who received QIVe (median age, 41 years) to determine the effectiveness of the vaccines in preventing influenza-like illness (ILI). The patients were aged 4 years and older and had received either vaccine in primary care in the U.S.

According to the study findings, after adjusting for age, sex, health status and geographic region, the QIVc was found to be 36.2% more effective than the QIVe in preventing ILI (95% CI, 26.1%-44.9%).

“The study indicates that cell-based vaccines should be considered for all patients over the age of 4, as QIVc may result in better influenza-related outcomes compared to standard vaccine options in some seasons, particularly those characterized by egg-adapted changes, as last year was,” Sylvester said.

He said real-world evidence is of growing importance as a complement to clinical studies.

“[It] is particularly relevant to influenza vaccines given the changing nature of the virus, and we are starting to see a paradigm shift in how it’s acknowledged by top experts globally,” Sylvester said. – by Bruce Thiel

Reference:

Boikos C, et al. Effectiveness of the cell culture- and egg-derived, seasonal influenza vaccine during the 2017-2018 Northern Hemisphere influenza season. Presented at the National Foundation for Infectious Diseases 2018 Clinical Vaccinology Course.

Disclosure: Sylvester works for Seqirus.