Pfizer COVID-19 vaccine
Pfizer COVID-19 vaccineKobi Richter/TPS

A preliminary report on the Pfizer vaccine indicates that its effectiveness at preventing infections -96% at its highest, some two months after the second dose - can fall by more than ten percent by the six-month mark. The study found a decline of roughly six percent per month, meaning that it could be less than 50% effective within two years.

The report emphasizes that these findings are strictly regarding the levels of infection; serious symptoms and hospitalization are still reduced by over 90% even well after the vaccine.

According to MSN, the manufacturers claim that a third "booster" shot of the vaccine would provide significantly increased protection, including against the new and more virulent Delta strain; antibody levels in those 18 to 55 after a booster shot were found to be five times higher than those in a patient who had received only two vaccinations.

The study was conducted by a team from the Cold Spring Harbor Laboratory on a test group of 23 patients. The study has not yet been peer-reviewed, but Dr. Mikael Dolsten, who leads worldwide research and development for Pfizer, says that the preliminary data are 'very encouraging. His company plans to ask the FDA to approve a booster shot against COVID-19 as soon as next month.