Clinicians should have a “high level of suspicion” about possible COVID-19 symptoms in the two weeks following vaccination, results of a new study in healthcare workers suggest.
Investigators followed patient outcomes in a worker vaccination program at a large Israeli hospital. The first doses of the Pfizer-BioNTech vaccine were given in December, during a national surge in cases. Workers who already had recovered from COVID-19 were excluded.
Among more than 4,000 vaccinated hospital staff members, 22 developed COVID-19 from one to 10 days following immunization (a median 3.5 days). Thirteen workers were tested after showing symptoms (typically including fever, chills, cough, headache, muscle aches and sore throat). Two others were tested due to exposure to confirmed or suspected COVID-19 cases, and asymptomatic cases were found as part of post-exposure screening, reported Gili Regev-Yochay, M.D., of Harvard and Chaim Sheba Medical Center, in Israel.
The takeaway? “Clinicians should not dismiss post-vaccination symptoms as vaccine-related and should promptly test for COVID-19,” Regev-Yochay and colleagues wrote.
The Pfizer-BioNTech vaccine is not likely protective against clinical disease the first days after the first dose is given, according to results of clinical trials. Although protection increases to 52% a week after the first dose, positive COVID-19 test results have been found among vaccine recipients even early after the second dose.
“Thus, during a large-scale immunization campaign coinciding with rapid national increase in COVID-19 cases, some immunized persons likely will develop clinical disease,” the authors of the hospital study concluded.
An article was published in the journal Emerging Infectious Diseases.
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