The New Jersey Department of Health is investigating a number of Covid-19 infections in people who have been fully vaccinated, Governor Murphy announced Monday. 

Of the 4.4 million New Jerseyans who have received both doses of a Covid-19 vaccine, or a single dose of the Johnson & Johnson vaccine, the Health Department has recorded 39 positive Covid-19 tests among them. That would still mean the vaccines are 99.9993% effective.

Governor Murphy said the numbers reflect the effectiveness of the vaccines and how the pandemic is still ongoing – but only among the unvaccinated.

Several recent studies have suggested that the current Covid-19 vaccines may not be as effective against the hyper-transmissible Delta variant of the virus that is currently sweeping the globe, although most vaccinated individuals remain well protected.

Pfizer and Moderna have been working on a Covid-19 booster shot to protect against the Delta and other variants, although the CDC says that no additional shots are necessary at this time.