The coronavirus vaccine is effective in protecting those who are fully inoculated even in case of prolonged exposure to infected family members, a new Israeli study has found.
A team from Ziv Medical Center in Safed led by Dr. Shimon Edelstein, head of the Infectious Diseases Unit, tracked hospital employees whose family members were infected with the virus. Their findings were published in the Journal of Medical Infection last week.
According to the study, about 12% of Ziv Medical Center’s 1,800 employees have contracted COVID-19 since the beginning of the pandemic. By the end of January, more than 90% of those eligible had been fully vaccinated.
“Despite the herd immunity of the medical staff, most of them returned home to locations where the epidemic was raging, in communities in which more than 7% of members were verified COVID-19-positive,” the authors wrote. “Vaccinated workers did not have to quarantine even if a verified patient resided in their home, and they were allowed to continue working regularly at the hospital, unless they developed suspicious clinical symptoms for COVID-19. However, prolonged exposure to a positive family member living in the same house may be a challenge to the immune system, unlike exposure to a positive patient for a short period.”
Some 14 relevant cases were considered: 13 fully vaccinated staff, including nurses, doctors and administrators, and one recovered patient. They all lived with an undiagnosed infected person.
Each employee was administered several PCR tests after the disease was discovered.
“All PCR SARS-CoV-2 tests performed for the 14 workers after exposure (33 tests) were found to be negative: no carriers were found, the researchers concluded,” the report said. “These findings are encouraging, especially in light of the way mRNA triggers the immune system.”
Several studies have indicated that the Pfizer vaccine, which is the one currently used in Israel, is about 95% effective in preventing infection.
The vaccine’s ability to protect even in case of close and prolonged proximity with a patient is a positive development concerning its efficacy, the researchers wrote.