Introduction. In the attempt to control the spread of the disease and the pandemic, numerous COVID-19 vaccines are in development. A review of the evidence on their efficacy and safety are critical. Methods. A search for trials was done using the COVID-19 Living OVerview of Evidence (L·OVE) platform. We also searched for relevant authorization documents and trial reports for COVID-19 vaccines of the US-Food and Drug Authority (US-FDA), the European Medicines Agency (EMA), the United Kingdom Medicines and Health Products Regulatory Agency (MHRA), and the WHO website. We included studies that fulfilled the following inclusion criteria: population – humans; intervention – COVID-19 vaccines; comparison – control or placebo; outcomes – efficacy and adverse events; methods – phase 3 randomized trials. Two reviewers independently screened the reports, assessed the methodological quality, and extracted the data on the trial characteristics and results on vaccine efficacy and safety. The date of last search was March 11, 2021. Results. Interim results of trials investigating five vaccines were identified and included in the review. All five vaccines demonstrated satisfactory vaccine efficacy (VE) against symptomatic COVID-19 infection among adults in the short term with moderate certainty of evidence: BNT162b2, VE 95% (95% CI 90.3, 97.6); mRNA-1273, VE 93.6% (95% CI 88.6, 96.5); ChAdOx1, VE 66.7% (95% CI 57.4, 74.0), Gam-COVID-Vac, VE 91.1% (95% CI 83.6, 95.1); and Ad26.CoV2.S, VE 67.2% (95% CI 59.3, 73.7). Data on the efficacy against severe COVID-19 infection and asymptomatic COVID-19 infection are still inconclusive, except for Ad26.CoV2.S, which demonstrated good efficacy in preventing moderate and/or severe COVID-19 infection and acceptable protection against asymptomatic COVID-19 infection 28 days after vaccination (moderate certainty of evidence). Efficacy data on preventing death from COVID-19 infection are still inconclusive. Very limited phase 3 trial data is available to inform vaccine efficacy against the different variants of SARS-CoV-2. Vaccination with these five vaccines was associated with higher adverse reactions compared to control. These adverse events, due to reactions to the vaccines, were mild to moderate and of short duration. Available evidence on vaccine efficacy and safety is limited, mainly due to the short follow up and the small sample size of specific populations. Conclusion. BNT162b2, mRNA-1273, ChAdOx1, Gam-COVID-Vac and Ad26.CoV.S vaccines demonstrated satisfactory vaccine efficacy against symptomatic COVID-19 infection among adults in the short term with moderate certainty of evidence. Data on the efficacy against severe COVID-19 infection, asymptomatic COVID-19 infection, and death from COVID-19 infection are still inconclusive. Long-term efficacy and safety data, and data on the efficacy against variant strains of SARS-CoV-2 are still lacking.
Humans ; COVID-19 Vaccines ; COVID-19

Background. The use of face shield in addition to face mask is thought to reduce the transmission of SARS-CoV-2 by blocking respiratory droplets and by preventing one from touching facial orifices.

Objective. To determine the effectiveness of face mask with face shield, compared to face mask alone, in reducing transmission of SARS-CoV-2.

Methods. We searched MEDLINE, Cochrane Library, as well as trial registers, preprint sites and COVID-19 living evidence sites as of 30 September 2021. We included studies that used face shield with face mask versus face mask alone to prevent COVID-19. We screened studies, extracted data, assessed the risk of bias and certainty of evidence using the GRADE approach. Review Manager 5.4 was used to estimate pooled effects.

Results. There is no available direct evidence for face shield plus face mask versus face mask alone in the general public. Five (5) observational studies with very low certainty of evidence due to serious risk of bias and indirectness were included. Participants in all the studies were health care workers (HCWs) who used the face shield with their standard personal protective equipment (PPE). Four (4) of the studies were in the hospital setting (three case control studies, one pre- and post-surveillance study); one was done in the community (one pre- and post-surveillance study) in which HCWs visited the residence of the contacts of SARS-CoV-2 positive patients. The case control studies done in the hospital setting showed a trend toward benefit with the use of face shield or goggle but this was inconclusive (OR 0.85, 95% CI 0.68-1.08) while the pre- and post-surveillance study showed significant benefit when face shield (OR 0.28, 95% CI 0.22-0.37) use became a requirement for HCWs upon hospital entry. In the study done in the community setting, significant protection for HCWs was noted with the use of face shield (OR 0.04, 95% CI 0.00-0.69) but the results were limited by serious risk of bias and imprecision.

Conclusion. In the hospital setting, there was a lower likelihood of COVID-19 infection in HCWs who used a face shield or goggles on top of their PPE. For the general public in the community, there is presently no study on the use of face shield in addition to the face mask to prevent COVID-19 infection.

Personal Protective Equipment ; COVID-19 ; Eye Protective Devices