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 has suggested.
While the study that was published in the journal Emerging Infectious Disease based its conclusion following patients outcomes in a worker vaccination programme at a large Israeli hospital where they were given the first doses of the Pfizer-BioNTech vaccine given December last year, such cases have emerged in India too where healthcare workers are being given Covishield and Covaxin.
For instance, five doctors in Chamarajanagar district in Karnataka in India tested positive for Covid-19 a week after they got the first shot of the vaccine in January last this year.
The Israeli study had excluded workers who already had recovered from Covid-19.
Among more than 4,000 vaccinated hospital staff members, 22 developed Covid-19 from one to 10 days following immunisation (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 immunisation campaign coinciding with rapid national increase in Covid-19 cases, some immunised persons likely will develop clinical disease,” the authors of the hospital study concluded.
Health experts have called for the need to practice precautions like wearing masks, social distancing norms, hand washing and avoiding crowded areas.
Those who have received both shots of the vaccine should follow all precautions until a significant percentage of the population has been vaccinated, as per health experts.
