Coronavirus disease 2019 (COVID-19) mRNA vaccine effectiveness in asymptomatic healthcare workers

Abstract

would have been low. Additionally, viral interference, with SARS-CoV-2 being the dominant respiratory pathogen, might have contributed to the decrease in rates of other respiratory viral illnesses. This idea is not unfounded. During the H1N1 pandemic in 2009, while the number of H1N1 influenza cases increased, the incidence of seasonal influenza and RSV decreased significantly compared to prior years. This trend lasted until the H1N1 strain transitioned from a pandemic to a seasonal virus the following year. 9 In conclusion, SARS-CoV-2 was the dominant pathogen, while other community respiratory viral and group A Streptococcus throat infections markedly declined in frequency in both adults and children during the 2020-2021 season compared to 2019-2020. The reason for the decline may be attributed to the mitigating measures widely employed in the community. Although it is difficult to predict the incidence of respiratory viral infections after the resolution of the COVID-19 pandemic, it is likely that the number of non-SARS-CoV-2 respiratory infections will rise back to normal in the coming years as SARS-CoV-2 becomes a seasonal virus.

Evaluation of the Effectiveness and Safety of the BNT162b2 COVID-19 Vaccine in the Vaccination Campaign among the Health Workers of Fondazione Policlinico Universitario Agostino Gemelli IRCCS

“…As it concerns the effectiveness assessment, our findings (91.5%; 95% CI, 84.7% to 95.3%) were in line with those observed in the scientific literature [ 29 , 30 ]. Moreover, focusing on the hospital setting and on a specific population (i.e., health workers), evidence in the literature showed a slightly lower vaccine effectiveness with respect to our results [ 17 , 18 , 19 , 20 ]. The difference in vaccine effectiveness could be explained by the differences in the definition of vaccine breakthrough [ 22 ] and also probably by the strict hospital policy and procedures through which it incentivizes the continuous usage of individual protection devices, such as surgical and FFP2 face masks, and the proper physical distancing.…”

“…As highlighted by the WHO [ 13 ], COVID-19 vaccines have been proven as safe, effective, and life-saving against this severe disease in several large vaccine trials [ 8 , 14 , 15 , 16 ]. Several studies have been conducted to assess the effectiveness of vaccination campaigns in the health care workers in real-world settings [ 17 , 18 , 19 , 20 ]. We add to this evidence by providing an assessment of the effectiveness and safety of (BNT162b2) vaccine among the health workers of Fondazione Policlinico Universitario Agostino Gemelli IRCCS (FPG), a large teaching hospital in Rome (Italy).…”

Effectiveness of BNT162b2 and ChAdOx1 Vaccines against Symptomatic COVID-19 among Healthcare Workers in Kuwait: A Retrospective Cohort Study

“…Healthcare workers have been given the priority for vaccination in Kuwait as in most countries; therefore, efforts are needed to better understand reasons for vaccine hesitancy in this high-risk exposure group. Other studies have reported that most HCWs were vaccinated with at least one dose within two to three months of vaccine roll-out (i.e., 90% in UK; 79% in Israel; 75% in USA, 73.5% in Spain) [ 4 , 7 , 8 , 9 ].…”

“…For instance, in a study from the US CDC, the authors reported that vaccine effectiveness against SARS-CoV-2 infection among HCWs with full immunization (≥14 days after BNT162b2 second dose) was 90% (95% CI = 68–97%) [ 8 ]. In other studies on HCWs, BNT162b2 vaccine effectiveness against SARS-CoV-2 infection (≥7 day post second dose) was 85% (95% CI = 74–96%) in the UK [ 4 ],90.6% (Cis were not provided) ≥7 day post second dose in Spain [ 9 ], 94.2% (CI: 88.5%-98.1%) after second dose in Greece [ 19 ], and 85% (95% CI = 71–92%) 15–24 days after second dose in Israel [ 7 ]. In another study from Italy, authors reported that BNT162b2 vaccine among HCWs reduced COVID-19 incidence rate and symptom durations significantly after 13–21 days from a single dose administration [ 20 ].…”

“…However, early findings showed that the uptake percentage varies between countries. For instance, most HCWs were vaccinated with at least one dose within two to three months from the vaccine roll-out in several countries (e.g., it was 90% in UK; 79% in Israel; 75% in USA, and 73.5% in Spain) [ 4 , 7 , 8 , 9 ]. However, in this region, a questionnaire-based study from Saudi Arabia reported that only 33.3% of HCWs enrolled to receive or had already received the vaccine with a greater proportion being females, those of younger age (20–40 years), and those who are Saudi nationals [ 10 ].…”