Effectiveness of two COVID-19 vaccines (viral vector and inactivated viral vaccine) against SARS-CoV-2 infection in a cohort of healthcare workers.

OBJECTIVES: We aimed to investigate real-world vaccine effectiveness (VE) for Oxford-AstraZeneca (ChAdOx1) and CoronaVac against laboratory-confirmed COVID-19 infection among healthcare workers (HCWs). METHODS: We conducted a retrospective cohort study among HCWs (aged ≥18 years) working in a private healthcare system in Brazil between January 1, 2021 and August 3, 2021. To assess VE, we calculated VE=1-RR (rate ratio), with RR determined by adjusting Poisson models with the occurrence of COVID-19 infection as the outcome, and the vaccination status as the main exploratory variable. We used the logarithmic link function and simple models adjusting for sex, age and job types. RESULTS: 13,813 HCWs met the inclusion criteria for this analysis. 6,385 (46.2%) received the CoronaVacvaccine, 5,916 (42.8%) received the ChAdOx1 vaccine, and 1,512 (11.0%) were not vaccinated. Overall, COVID-19 infection cases happened in 6% of unvaccinated HCWs, 3% of HCWs receiving two doses of CoronaVacvaccine, and 0.7% of HCWs receiving two doses of ChAdOx1 vaccine (p-value< 0.001). In the adjusted analyses, the estimated VE was 51.3% for CoronaVac, and 88.1% for ChAdOx1 vaccine. Both vaccines reduced the number of hospitalizations, the length of hospital stay, and the need of mechanical ventilation. Nineteen SARSCoV-2 samples from nineteen HCWs were screened for mutations of interest. Eighteen out of nineteen of those samples were Gamma SARS-CoV-2 variant. CONCLUSIONS: While both COVID-19 vaccines (viral vector and inactivated virus) can significantly prevent COVID-19 infection among HCWs, CoronaVac was much less effective. The COVID-19 vaccines were also effective even against a dominant Gamma variant.

Effectiveness of heterologous COVID-19 vaccine booster dosing in Brazilian healthcare workers, 2021.

OBJECTIVES: Little is currently known about vaccine effectiveness (VE) for either two doses of Oxford-AstraZeneca (ChAdOx1) viral vector vaccine or CoronaVac inactivated viral vaccine followed by a third dose of mRNA vaccine (Pfizer/BioNTech) among healthcare workers (HCWs). METHODS: We conducted a retrospective cohort study among HCWs (aged ≥18 years) working in a private healthcare system in Brazil from January to December 2021. VE was defined as 1-IRR (incidence rate ratio), with IRR determined using Poisson models with the occurrence of laboratory-confirmed COVID-19 infection as the outcome, adjusting for age, sex, and job type. We compared those receiving viral vector or inactivated viral primary series (two doses) to those who received an mRNA booster. RESULTS: A total of 11,427 HCWs met the inclusion criteria. COVID-19 was confirmed in 31.5% of HCWs receiving two doses of CoronaVac vaccine vs. 0.9% of HCWs receiving two doses of CoronaVac vaccine with mRNA booster (p < 0.001), and 9.8% of HCWs receiving two doses of ChAdOx1 vaccine vs. 1% among HCWs receiving two doses of ChAdOx1 vaccine with mRNA booster (p < 0.001). In the adjusted analyses, the estimated VE was 92.0% for two CoronaVac vaccines plus mRNA booster, and 60.2% for two ChAdOx1 vaccines plus mRNA booster, when compared to those with no mRNA booster. Of 246 samples screened for mutations, 191 (77.6%) were Delta variants. CONCLUSIONS: While two doses of ChAdOx1 or CoronaVac vaccines prevent COVID-19, the addition of a Pfizer/BioNTech booster provided significantly more protection.

The effectiveness of coronavirus disease 2019 (COVID-19) vaccine in the prevention of post-COVID-19 conditions: A systematic literature review and meta-analysis.

Background: Although multiple studies have revealed that coronavirus disease 2019 (COVID-19) vaccines can reduce COVID-19-related outcomes, little is known about their impact on post-COVID-19 conditions. We performed a systematic literature review and meta-analysis on the effectiveness of COVID-19 vaccination against post-COVID-19 conditions (ie, long COVID). Methods: We searched PubMed, CINAHL, EMBASE, Cochrane Central Register of Controlled Trials, Scopus, and Web of Science from December 1, 2019, to April 27, 2022, for studies evaluating COVID-19 vaccine effectiveness against post-COVID-19 conditions among individuals who received at least 1 dose of Pfizer/BioNTech, Moderna, AstraZeneca, or Janssen vaccine. A post-COVID-19 condition was defined as any symptom that was present 3 or more weeks after having COVID-19. Editorials, commentaries, reviews, study protocols, and studies in the pediatric population were excluded. We calculated the pooled diagnostic odds ratios (DORs) for post-COVID-19 conditions between vaccinated and unvaccinated individuals. Vaccine effectiveness was estimated as 100% × (1 - DOR). Results: In total, 10 studies with 1,600,830 individuals evaluated the effect of vaccination on post-COVID-19 conditions, of which 6 studies were included in the meta-analysis. The pooled DOR for post-COVID-19 conditions among individuals vaccinated with at least 1 dose was 0.708 (95% confidence interval (CI), 0.692-0.725) with an estimated vaccine effectiveness of 29.2% (95% CI, 27.5%-30.8%). The vaccine effectiveness was 35.3% (95% CI, 32.3%-38.1%) among those who received the COVID-19 vaccine before having COVID-19, and 27.4% (95% CI, 25.4%-29.3%) among those who received it after having COVID-19. Conclusions: COVID-19 vaccination both before and after having COVID-19 significantly decreased post-COVID-19 conditions for the circulating variants during the study period although vaccine effectiveness was low.

Association between job role and coronavirus disease 2019 (COVID-19) among healthcare personnel, Iowa, 2021.

We describe the association between job roles and coronavirus disease 2019 (COVID-19) among healthcare personnel. A wide range of hazard ratios were observed across job roles. Medical assistants had higher hazard ratios than nurses, while attending physicians, food service workers, laboratory technicians, pharmacists, residents and fellows, and temporary workers had lower hazard ratios.

The short-term effectiveness of coronavirus disease 2019 (COVID-19) vaccines among healthcare workers: a systematic literature review and meta-analysis.

Objective: Healthcare workers (HCWs) are at risk of COVID-19 due to high levels of SARS-CoV-2 exposure. Thus, effective vaccines are needed. We performed a systematic literature review and meta-analysis on COVID-19 short-term vaccine effectiveness among HCWs. Methods: We searched PubMed, CINAHL, EMBASE, Cochrane Central Register of Controlled Trials, Scopus, and Web of Science from December 2019 to June 11, 2021, for studies evaluating vaccine effectiveness against symptomatic COVID-19 among HCWs. To meta-analyze the extracted data, we calculated the pooled diagnostic odds ratio (DOR) for COVID-19 between vaccinated and unvaccinated HCWs. Vaccine effectiveness was estimated as 100% × (1 - DOR). We also performed a stratified analysis for vaccine effectiveness by vaccination status: 1 dose and 2 doses of the vaccine. Results: We included 13 studies, including 173,742 HCWs evaluated for vaccine effectiveness in the meta-analysis. The vast majority (99.9%) of HCWs were vaccinated with the Pfizer/BioNTech COVID-19 mRNA vaccine. The pooled DOR for symptomatic COVID-19 among vaccinated HCWs was 0.072 (95% confidence interval [CI], 0.028-0.184) with an estimated vaccine effectiveness of 92.8% (95% CI, 81.6%-97.2%). In stratified analyses, the estimated vaccine effectiveness against symptomatic COVID-19 among HCWs who had received 1 dose of vaccine was 82.1% (95% CI, 46.1%-94.1%) and the vaccine effectiveness among HCWs who had received 2 doses was 93.5% (95% CI, 82.5%-97.6%). Conclusions: The COVID-19 mRNA vaccines are highly effective against symptomatic COVID-19, even with 1 dose. More observational studies are needed to evaluate the vaccine effectiveness of other COVID-19 vaccines, COVID-19 breakthrough after vaccination, and vaccine efficacy against new variants.

Coronavirus disease 2019 (COVID-19) among nonphysician healthcare personnel by work location at a tertiary-care center, Iowa, 2020-2021.

We describe COVID-19 cases among nonphysician healthcare personnel (HCP) by work location. The proportion of HCP with coronavirus disease 2019 (COVID-19) was highest in the emergency department and lowest among those working remotely. COVID-19 and non-COVID-19 units had similar proportions of HCP with COVID-19 (13%). Cases decreased across all work locations following COVID-19 vaccination.

Corowa-kun: A messenger app chatbot delivers COVID-19 vaccine information, Japan 2021.

BACKGROUND: There is a long history in Japan of public concerns about vaccine adverse events. Few studies have assessed how mobile messenger apps affect COVID-19 vaccine hesitancy. METHODS: Corowa-kun, a free chatbot, was created on February 6, 2021 in LINE, the most popular messenger app in Japan. Corowa-kun provides instant, automated answers to 70 frequently asked COVID-19 vaccine questions. A cross-sectional survey with 21 questions was performed within Corowa-kun during April 5-12, 2021. RESULTS: A total of 59,676 persons used Corowa-kun during February-April 2021. Of them, 10,192 users (17%) participated in the survey. Median age was 55 years (range 16-97), and most were female (74%). COVID-19 vaccine hesitancy reported by survey respondents decreased from 41% to 20% after using Corowa-kun. Of the 20% who remained hesitant, 16% (1,675) were unsure, and 4% (364) did not intend to be vaccinated. Factors associated with vaccine hesitancy were: age 16-34 (odds ratio [OR] = 3.7; 95% confidential interval [CI]: 3.0-4.6, compared to age ≥ 65), female sex (OR = 2.4; Cl: 2.1-2.8), and history of a previous vaccine side-effect (OR = 2.5; Cl: 2.2-2.9). Being a physician (OR = 0.2; Cl: 0.1-0.4) and having received a flu vaccine the prior season (OR = 0.4; Cl: 0.3-0.4) were protective. CONCLUSIONS: A substantial number of people used the chabot in a short period. Mobile messenger apps could be leveraged to provide accurate vaccine information and to investigate vaccine intention and risk factors for vaccine hesitancy.

The long-term effectiveness of coronavirus disease 2019 (COVID-19) vaccines: A systematic literature review and meta-analysis.

Background: Although multiple studies revealed high vaccine effectiveness of coronavirus disease 2019 (COVID-19) vaccines within 3 months after the completion of vaccines, long-term vaccine effectiveness has not been well established, especially after the δ (delta) variant became prominent. We performed a systematic literature review and meta-analysis of long-term vaccine effectiveness. Methods: We searched PubMed, CINAHL, EMBASE, Cochrane Central Register of Controlled Trials, Scopus, and Web of Science from December 2019 to November 15, 2021, for studies evaluating the long-term vaccine effectiveness against laboratory-confirmed COVID-19 or COVID-19 hospitalization among individuals who received 2 doses of Pfizer/BioNTech, Moderna, or AstraZeneca vaccines, or 1 dose of the Janssen vaccine. Long-term was defined as >5 months after the last dose. We calculated the pooled diagnostic odds ratio (DOR) with 95% confidence interval for COVID-19 between vaccinated and unvaccinated individuals. Vaccine effectiveness was estimated as 100% × (1 - DOR). Results: In total, 16 studies including 17,939,172 individuals evaluated long-term vaccine effectiveness and were included in the meta-analysis. The pooled DOR for COVID-19 was 0.158 (95% CI: 0.157-0.160) with an estimated vaccine effectiveness of 84.2% (95% CI, 84.0- 84.3%). Estimated vaccine effectiveness against COVID-19 hospitalization was 88.7% (95% CI, 55.8%-97.1%). Vaccine effectiveness against COVID-19 during the δ variant period was 61.2% (95% CI, 59.0%-63.3%). Conclusions: COVID-19 vaccines are effective in preventing COVID-19 and COVID-19 hospitalization across a long-term period for the circulating variants during the study period. More observational studies are needed to evaluate the vaccine effectiveness of third dose of a COVID-19 vaccine, the vaccine effectiveness of mixing COVID-19 vaccines, COVID-19 breakthrough infection, and vaccine effectiveness against newly emerging variants.

Impact of COVID-19 on an infection prevention and control program, Iowa 2020-2021.

BACKGROUND: The COVID-19 pandemic has affected infection prevention and control (IPC) programs worldwide. We evaluated the impact of COVID-19 on the University of Iowa Hospitals & Clinics IPC program by measuring the volume of calls to the program, changes in healthcare-associated infection rates, and team member perceptions. METHODS: We retrieved the IPC call log and healthcare-associated infection trends for 2018-2020. We defined 2 periods: pre-COVID-19 (2018-2019) and COVID-19 (January-December 2020). We also conducted one-on-one interviews and focus group interviews with members of the IPC program and describe changes in their working conditions during the COVID-19 period. RESULTS: A total of 6,564 calls were recorded during 2018-2020. The pre-COVID-19 period had a median of 71 calls and/or month (range: 50-119). During the COVID-19 period, the median call volume increased to 368/month (range: 149-829), and most calls were related to isolation precautions (50%). During the COVID-19 period, the central line-associated bloodstream infection incidence increased significantly. Infection preventionists reported that the ambiguity and conflicting guidance during the pandemic were major challenges. CONCLUSIONS: Our IPC program experienced a 500% increase in consultation requests. Planning for future bio-emergencies should include creative strategies to increase response capacity within IPC programs.

Short-term effectiveness of COVID-19 vaccines in immunocompromised patients: A systematic literature review and meta-analysis.

OBJECTIVES: We aimed to assess the short-term effectiveness of COVID-19 vaccines among immunocompromised patients to prevent laboratory-confirmed symptomatic COVID-19 infection. METHODS: Systematic review and meta-analysis. We calculated the pooled diagnostic odds ratio [DOR] (95% CI) for COVID-19 infection between immunocompromised patients and healthy people or those with stable chronic medical conditions. VE was estimated as 100% x (1-DOR). We also investigated the rates of developing anti-SARS-CoV-2 spike protein IgG between the 2 groups. RESULTS: Twenty studies evaluating COVID-19 vaccine response, and four studies evaluating VE were included in the meta-analysis. The pooled DOR for symptomatic COVID-19 infection in immunocompromised patients was 0.296 (95% CI: 0.108-0.811) with an estimated VE of 70.4% (95% CI: 18.9%- 89.2%). When stratified by diagnosis, IgG antibody levels were much higher in the control group compared to immunocompromised patients with solid organ transplant (pOR 232.3; 95% Cl: 66.98-806.03), malignant diseases (pOR 42.0, 95% Cl: 11.68-151.03), and inflammatory rheumatic diseases (pOR 19.06; 95% Cl: 5.00-72.62). CONCLUSIONS: We found COVID-19 mRNA vaccines were effective against symptomatic COVID-19 among the immunocompromised patients but had lower VE compared to the controls. Further research is needed to understand the discordance between antibody production and protection against symptomatic COVID-19 infection.

Coronavirus Disease 2019 Serial Testing Among Hospitalized Patients in a Midwest Tertiary Medical Center, July-September 2020.

We implemented serial coronavirus disease 2019 testing for inpatients with a negative test on admission. The conversion rate (negative to positive) on repeat testing was 1%. We identified patients during their incubation period and hospital-onset cases, rapidly isolated them, and potentially reduced exposures. Serial testing and infectiousness determination were resource intensive.

Coronavirus disease 2019 (COVID-19) incidence after exposures in shared patient rooms in a tertiary-care center in Iowa, July 2020-May 2021.

The incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure in shared patient rooms was low at our institution: 1.8 per 1,000 shared-room patient days. However, the secondary attack rate (21.6%) was comparable to that reported in household exposures. Lengthier exposures were associated with SARS-CoV-2 conversion. Hospitals should implement measures to decrease shared-room exposures.

Coronavirus disease 2019 (COVID-19) admission screening and assessment of infectiousness at an academic medical center in Iowa, 2020.

OBJECTIVE: Patients admitted to the hospital may unknowingly carry severe acute respiratory coronavirus virus 2 (SARS-CoV-2), and hospitals have implemented SARS-CoV-2 admission screening. However, because SARS-CoV-2 reverse-transcription polymerase chain reaction (RT-PCR) assays may remain positive for months after infection, positive results may represent active or past infection. We determined the prevalence and infectiousness of patients who were admitted for reasons unrelated to COVID-19 but tested positive for SARS-CoV-2 on admission screening. METHODS: We conducted an observational study at the University of Iowa Hospitals & Clinics from July 7 to October 25, 2020. All patients admitted without suspicion of COVID-19 were included, and medical records of those with a positive admission screening test were reviewed. Infectiousness was determined using patient history, PCR cycle threshold (Ct) value, and serology. RESULTS: In total, 5,913 patients were screened and admitted for reasons unrelated to COVID-19. Of these, 101 had positive admission RT-PCR results; 36 of these patients were excluded because they had respiratory signs/symptoms on admission on chart review. Also, 65 patients (1.1%) did not have respiratory symptoms. Finally, 55 patients had Ct values available and were included in this analysis. The median age of the final cohort was 56 years and 51% were male. Our assessment revealed that 23 patients (42%) were likely infectious. The median duration of in-hospital isolation was 5 days for those likely infectious and 2 days for those deemed noninfectious. CONCLUSIONS: SARS-CoV-2 was infrequent among patients admitted for reasons unrelated to COVID-19. An assessment of the likelihood of infectiousness using clinical history, RT-PCR Ct values, and serology may help in making the determination to discontinue isolation and conserve resources.