Results from the study data reinforce the need to adhere to public health measures by people who have been vaccinated.
While vaccines for COVID-19 offer high efficacy and strong protection against the disease, It is still possible that individuals are able to contract the virus.
Perhaps no other population is more susceptible than healthcare workers who are on the frontlines and have face-to-face contact with sick patients regularly.
Investigators from the Medical University of South Carolina recently set out to surveil COVID-19 rates among care team members from their facility following vaccination.
For the study, care team members who were diagnosed with COVID-19 subsequent of receiving a vaccination with the Pfizer-BioNTech shot self-identified during online electronic contact tracing surveys.
The investigators recorded data including demographics, symptoms and dates of symptoms. The care team members who tested positive were linked to viral burden data from nasopharyngeal swabs tested on Abbott PCR platforms.
Findings from the study showed that of the 111 care team members who tested positive after vaccination, 99 tested positive following 1 dose and 12 tested positive following 2 doses at a median of 10 and 5 days, respectively.
Of the care team members who reported symptoms, 104 did so after a median of 7 days from the time of vaccination to symptom onset, with 8 of them reporting symptoms before vaccination, 9 on the day of vaccination, and 3, 6, and 11 of them at 1, 2, and 3 days after vaccination, respectively. The most frequent jobs testing positive were nurses and physicians.
Additional findings from contact tracing showed that sources of transmission were household clusters, local transmission, occupational acquisition and travel-related transmission.
The majority of the cases following a vaccination occurred in care team members with infection incubating prior to the shot.
Contagion spoke to Scott Curry, MD, assistant professor in the college of medicine at the medical university of south Carolina, who presented the research at The Society for Healthcare Epidemiology of America Conference 2021, about the study.