The Challenge of Finding the Unknown

The FDA Vaccines and Related Biologics Products Advisory Committee (VBPAC) unanimously voted on Oct. 15, 2021, to recommend an Emergency Use Authorization (EUA) for a booster dose of the Johnson & Johnson (J&J) COVID-19 vaccine for adults aged 18 or older at least two months following initial vaccination. This decision comes just one day after a similar recommendation for the Moderna COVID-19 vaccine. The vote followed findings from two J&J clinical trials. One was the Phase III ENSEMBLE 2 study which evaluated booster doses of the company’s COVID-19 vaccine administered two months after the single-shot. According to a company press release, these findings suggested increased protection (94%) against moderate-to-severe COVID-19 in the United States. J&J’s other clinical trial was a Phase I/IIa study evaluating a booster dose given six months after the first shot. According to the press release, this demonstrated a nine-fold increase in antibody levels one week after the booster and a 12-fold increase four weeks after the booster. In addition to the clinical trials, data from a real-world study that was conducted from March to the end of July, and then extended to the end of August 2021, was also supplied to the council. This study showed stable vaccine effectiveness of 76% for COVID-19 related infections and 81% for COVID-19-related hospitalizations. There was no evidence of reduced effectiveness over the study duration of six months, which included the time period in which the Delta variant became dominant in the US. However, sequencing data was not available for analysis. “Today’s recommendation is based on the totality of evidence, with clinical and real-world data showing that while a single shot offers strong and long-lasting protection against COVID-19, a booster given after the single-dose primary vaccination increases protection, in particular against symptomatic COVID-19,” said Paul Stoffels, vice-chairman of the Executive Committee and chief scientific officer, Johnson & Johnson, in the press release. Source: Johnson & Johnson