Influenza Vaccination and Health Outcomes in COVID-19 Patients: A Retrospective Cohort Study

Assessing the temporal and cause-effect relationship between myocarditis and mRNA COVID-19 vaccines. A retrospective observational study

OBJECTIVE

In 2021, the US Centers for Disease Control and Prevention reported increased cases of myocarditis and pericarditis in the United States after mRNA COVID-19 vaccines. Our study aims to estimate the incidence of myocarditis in Apulia (Southern Italy) and the cause-effect relationship between COVID-19 mRNA vaccines and the risk of myocarditis.

METHODS

The Apulian regional archive of hospital discharge forms was used to define the cases of myocarditis in Apulia, considering data from 2017 to 2022. The overall vaccination status of patients was assessed via data collected from the Regional Immunization Database. The history of SARS-CoV-2 infection was extracted from the Italian Institute of Health platform.

RESULTS

Since 2017, 5687 cases of myocarditis have been recorded in Apulian subjects; the overall incidence described a decreasing trend, with a slight increase in 0-40 years-old subjects. From 2021 to 2022, 2,930,276 doses of COVID-19 mRNA vaccines were administered; a diagnosis of myocarditis after the second dose of the mRNA vaccine was reported for 894 (0.03%) of Apulian inhabitants, with an incidence rate of 17.9 × 1,000,000 persons-month. The multivariate analysis, adjusted for age, sex, underlying medical conditions, and diagnosis of COVID-19, showed that mRNA vaccination is a protective factor for myocarditis even in younger subjects (aOR = 0.4; 95% CI = 0.3-0.5).

CONCLUSION

A temporal association between an exposure and an outcome is not equivalent to a causal association. Our study underlines how an approach that considers the other potential causes of myocarditis (primarily COVID-19) and a causality assessment must be prioritized in the study of the topic.

Vaccination against influenza viruses reduces infection, not hospitalization or death, from respiratory COVID-19: A systematic review and meta-analysis

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19 and has brought a huge burden in terms of human lives. Strict social distance and influenza vaccination have been recommended to avoid co-infections between influenza viruses and SARS-CoV-2. Scattered reports suggested a protective effect of influenza vaccine on COVID-19 development and severity. We analyzed 51 studies on the capacity of influenza vaccination to affect infection with SARS-CoV-2, hospitalization, admission to Intensive Care Units (ICU), and mortality. All subjects taken into consideration did not receive any anti-SARS-CoV-2 vaccine, although their status with respect to previous infections with SARS-CoV-2 is not known. Comparison between vaccinated and not-vaccinated subjects for each of the four endpoints was expressed as odds ratio (OR), with 95% confidence intervals (CIs); all analyses were performed by DerSimonian and Laird model, and Hartung-Knapp model when studies were less than 10. In a total of 61 029 936 subjects from 33 studies, influenza vaccination reduced frequency of SARS-CoV-2 infection [OR plus 95% CI = 0.70 (0.65-0.77)]. The effect was significant in all studies together, in health care workers and in the general population; distance from influenza vaccination and the type of vaccine were also of importance. In 98 174 subjects from 11 studies, frequency of ICU admission was reduced with influenza vaccination [OR (95% CI) = 0.71 (0.54-0.94)]; the effect was significant in all studies together, in pregnant women and in hospitalized subjects. In contrast, in 4 737 328 subjects from 14 studies hospitalization was not modified [OR (95% CI) = 1.05 (0.82-1.35)], and in 4 139 660 subjects from 19 studies, mortality was not modified [OR (95% CI) = 0.76 (0.26-2.20)]. Our study emphasizes the importance of influenza vaccination in the protection against SARS-CoV-2 infection.

Influenza vaccine coverage in 6months-64 years-old patients affected by chronic diseases: A retrospective cohort study in Italy

At the beginning of each flu season, the Italian Ministry of Health defines the categories at higher risk of influenza complications, for which vaccination is actively and freely offered. The vaccine coverage (VC) of the influenza vaccine in subjects from 6 months to 64 years of age suffering from diseases that increase the risk of complications from influenza during the 2020-2021 season was evaluated. Our study wants to evaluate the VCs of the influenza vaccine in these subjects during the 2020/2021 season in Apulia. The digital archives relative to the Apulian population were used. A retrospective cohort study design was performed. 484,636 Apulian residents aged between 6 months and 64 years suffered from at least one chronic disease; 139,222 of 484,636 subjects received the influenza vaccine (VC: 28.7%) from October 2020 to January 2021. Considering the single comorbidities, the greatest values are found for pathologies for which major surgical interventions are planned and chronic renal failure/adrenal insufficiency patients, while the worst for chronic liver diseases and pathologies for which major surgical interventions are planned. In any case, it would seem that better VC is achieved in subjects with more than one chronic condition. Influenza vaccination must be promoted as a central public health measure, also because by reducing the burden on hospitals, it can greatly benefit the management of COVID-19 patients. Greater efforts by public health institutions must be implemented in order to achieve better VC in the target categories, including chronic patients.

COVID-19 vaccination hesitancy among Italian parents: A systematic review and meta-analysis

In May 2021, the Italian government extended the COVID-19 vaccination campaign to 12- to 18-year-old subjects and, starting December 2021, vaccines were also offered to children between 5 and 11 years-old. Despite these efforts, suboptimal vaccination coverages are reported. The purpose of this review is to estimate the proportion of parents/caregivers of children and adolescents expressing COVID-19 vaccine hesitancy in Italy. The vaccine hesitation rate among parents of minors was 55.1% (95%CI: 43.8-66.1%). A higher value was evidenced in studies focusing on children (59.9%; 95%CI = 43.7-75.1%) compared to the ones focusing on adolescents (51.3%; 95%CI = 34.5-68.0%). The main reasons for unwillingness were the belief that the vaccine was unsafe or ineffective, fear of adverse events, and considering COVID-19 a non-threatening disease. The implementation of effective communication campaigns and health educational programs on safe pediatric vaccinations is essential to support strategies to bolster vaccination confidence.

The Complex Association between COPD and COVID-19

Chronic obstructive pulmonary disease (COPD) is significant cause of morbidity and mortality worldwide. There is mounting evidence suggesting that COPD patients are at increased risk of severe COVID-19 outcomes; however, it remains unclear whether they are more susceptible to acquiring SARS-CoV-2 infection. In this comprehensive review, we aim to provide an up-to-date perspective of the intricate relationship between COPD and COVID-19. We conducted a thorough review of the literature to examine the evidence regarding the susceptibility of COPD patients to COVID-19 infection and the severity of their disease outcomes. While most studies have found that pre-existing COPD is associated with worse COVID-19 outcomes, some have yielded conflicting results. We also discuss confounding factors such as cigarette smoking, inhaled corticosteroids, and socioeconomic and genetic factors that may influence this association. Furthermore, we review acute COVID-19 management, treatment, rehabilitation, and recovery in COPD patients and how public health measures impact their care. In conclusion, while the association between COPD and COVID-19 is complex and requires further investigation, this review highlights the need for careful management of COPD patients during the pandemic to minimize the risk of severe COVID-19 outcomes.

Vaccine coverage for recommended vaccines among splenectomised patients in Apulia, South Italy: a retrospective cohort study

OBJECTIVE

Splenectomised/asplenic patients have a 10-50 fold higher risk than the general population of developing overwhelming postsplenectomy infection. To control this risk, these patients have to receive a specific immunisation schedule, before or in the 2 weeks after the surgical intervention. The study aims to estimate vaccine coverage (VC) for recommended vaccines among splenectomised patients in Apulia (South Italy), and to define the determinants of vaccination uptake in this population.

DESIGN

Retrospective cohort study.

SETTING

Apulia, Southern Italy.

PARTICIPANTS

1576 splenectomised patients.

METHODS

The Apulian regional archive of hospital discharge forms (SDOs) was used to define the splenectomised Apulian inhabitants. The study period went from 2015 to 2020. The vaccination status for Streptococcus pneumoniae (13-valent conjugate anti-pneumococcal vaccine+PPSV23), Haemophilus influenzae type b (Hib; one dose), Neisseria meningitidis ACYW135 (two doses), Neisseria meningitidis B (two doses) and influenza (at least one dose of influenza vaccine before an influenza season after splenectomy) was assessed via data collected from the Regional Immunisation Database (GIAVA). In order to define a subject as fully immunised, we considered the Centers for Diseases Control and Prevention guidelines to define the optimal immunisation status.

RESULTS

Since 2015, 1576 Apulian inhabitants have undergone splenectomy; the VC for anti-Neisseria meningitidis B vaccine was 30.9%, for anti-Neisseria meningitidis ACYW135 was 27.7%, for anti-Streptococcus pneumoniae was 27.0%, for anti-Hib was 30.1%, and 49.2% received at least one dose of influenza vaccine before an influenza season after splenectomy. None of the patients splenectomised in 2015 and 2016 had received the recommended MenACYW₁₃₅ and PPSV23 booster doses 5 years after completing the basal cycles.

CONCLUSIONS

The results of our study highlight low VC values among Apulian splenectomised patients. The task of public health institutions is to implement new strategies aimed at increasing VC in this population, implementing educational measures for patients and families, training for general practitioners and specialists, and ad hoc communication campaigns.

Burden of COVID-19 disease and vaccine coverages in Apulian splenectomized patients: A retrospective observational study

Splenectomy/asplenia is a condition associated with immune-compromission and specific vaccines are recommended for these patients, including the anti-COVID-19 vaccine. Among the high-risk group for which vaccination was prioritized in Italy, the immunocompromised patients after therapies or treatments were included. The Apulian regional archive of hospital discharge forms was used to define the list of splenectomized Apulian inhabitants, considering data from 2015 through 2020. The overall vaccination status of asplenic patients was assessed via data collected from the Regional Immunization Database. The history of SARS-CoV-2 infection and the infectious disease outcomes were extracted from the Italian Institute of Health platform "Integrated surveillance of COVID-19 cases in Italy". 1219 Apulian splenectomized inhabitants were included; the incidence rate of SARS-CoV-2 infection was 15.0 per 100 persons-year with a proportion of re-infection equal to 6.4%; the proportion of hospitalization was 2.9%, with a case-fatality rate of 2.6%. The vaccine coverage (VC) for the anti-COVID-19 vaccine basal routine was 64.2%, for the first booster dose was 15.4%, and for the second booster dose was 0.6%. A multifactorial approach is needed to increase the vaccination uptake in this sub-group population and to increase the awareness of the asplenia-related risks to patients and health personnel.

Effectiveness of on-site influenza vaccination strategy in Italian healthcare workers: a systematic review and statistical analysis

INTRODUCTION

One of the main determinants of non-adherence to influenza vaccination among healthcare workers (HCWs) is lack of time to attend vaccination services. Therefore, international Public Health Organizations have recommended on-site influenza vaccination in order to improve vaccination coverage among HCWs.

AREAS COVERED

We conducted a systematic narrative review of the relevant literature to evaluate the effectiveness of this strategy among HCWs in Italy. Fifteen studies, selected among scientific articles available in MEDLINE/PubMed, ISI Web of Knowledge and Scopus and published from January 1^st, 2018, to May 31^st, 2022, were included. A significant relationship was evidenced between influenza vaccine uptake and adoption of an on-site outpatient clinic (OR = 2.06; 95%CI = 1.43-2.95). The review highlighted a significant increase in VC when on-site vaccination was implemented (even exceeding +150% compared to the previous season), among other measures. Nevertheless, none of the reported experiences proved to meet the minimum target of 75% VC among HCWs.

EXPERT OPINION

Despite strategies to achieve greater willingness to immunize in this category, mandatory vaccination appears to be the only one that can guarantee protection for HCWs and the patients they care for.

Influenza and Pneumococcal Vaccination and the Risk of COVID-19: A Systematic Review and Meta-Analysis

A number of studies have investigated the potential on-specific effects of some routinely administered vaccines (e.g., influenza, pneumococcal) on COVID-19 related outcomes, with contrasting results. In order to elucidate this discrepancy, we conducted a systematic review and meta-analysis to assess the association between seasonal influenza vaccination and pneumococcal vaccination with SARS-CoV-2 infection and its clinical outcomes. PubMed and medRxiv databases were searched up to April 2022. A random effects model was used in the meta-analysis to pool odds ratio (OR) and adjusted estimates with 95% confidence intervals (CIs). Heterogeneity was quantitatively assessed using the Cochran's Q and the I2 index. Subgroup analysis, sensitivity analysis and assessment of publication bias were performed for all outcomes. In total, 38 observational studies were included in the meta-analysis and there was substantial heterogeneity. Influenza and pneumococcal vaccination were associated with lower risk of SARS-CoV-2 infection (OR: 0.80, 95% CI: 0.75-0.86 and OR: 0.70, 95% CI: 0.57-0.88, respectively). Regarding influenza vaccination, it seems that the majority of studies did not properly adjust for all potential confounders, so when the analysis was limited to studies that adjusted for age, gender, comorbidities and socioeconomic indices, the association diminished. This is not the case regarding pneumococcal vaccination, for which even after adjustment for such factors the association persisted. Regarding harder endpoints such as ICU admission and death, current data do not support the association. Possible explanations are discussed, including trained immunity, inadequate matching for socioeconomic indices and possible coinfection.

Association between influenza vaccination and SARS-CoV-2 infection and its outcomes: systematic review and meta-analysis

BACKGROUND

World Health Organization recommends that influenza vaccines should benefit as much of the population as possible, especially where resources are limited. Corona virus disease 2019 (COVID-19) has become one of the greatest threats to health systems worldwide. The present study aimed to extend the evidence of the association between influenza vaccination and COVID-19 to promote the former.

METHODS

In this systematic review, four electronic databases, including the Cochrane Library, PubMed, Embase, and Web of Science, were searched for related studies published up to May 2022. All odds ratios (ORs) with 95% confidence intervals (CIs) were pooled by meta-analysis.

RESULTS

A total of 36 studies, encompassing 55,996,841 subjects, were included in this study. The meta-analysis for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection provided an OR of 0.80 (95% CI: 0.73-0.87). The statistically significant estimates for clinical outcomes were 0.83 (95% CI: 0.72-0.96) for intensive care unit admission, 0.69 (95% CI: 0.57-0.84) for ventilator support, and 0.69 (95% CI: 0.52-0.93) for fatal infection, while no effect seen in hospitalization with an OR of 0.87 (95% CI: 0.68-1.10).

CONCLUSION

Influenza vaccination helps limit SARS-CoV-2 infection and severe outcomes, but further studies are needed.

REGISTRATION

PROSPERO, CRD42022333747.

The Awareness and Attitude of Physicians to Older Adult Routine Vaccination Scheme

Purpose

Immunization is one of the main components of preventive medicine measures. Influenza, pneumococcal, tetanus, and shingles vaccines are recommended for older adults routinely. This study aimed to show the knowledge and attitudes of the physicians to older adults’ vaccination schemes.

Patients and Methods

An electronic self-reported questionnaire was sent to physicians between March and July 2021 in Turkey. Sociodemographic characteristics, professional experience, area of expertise, and practice setting of the participants were recorded. As multiple-choice questions; the routinely recommended vaccines, and vaccines suggested in their daily practice before and after the COVID-19 pandemic were enquired.

Results

A total of 435 participants were included in the study. 43.9% of the patients were primary family physicians, and 36.8% were internists. 63.4% of the participants had reported reviewing the National Vaccination Scheme. 94.5% of the medical doctors indicated that they had recommended any vaccination to their patients. 20.9% of the practitioners could select four or five of the routinely recommended vaccines. Reviewing the National Adult Vaccination Scheme and being an internist were positively related to predicting the recommended vaccines. The recommendation rates of influenza and pneumococcal conjugate (PCV13) were seen at 88% and 78%, respectively. Except for PCV13, recommendation rates of other routine vaccines were decreased after the pandemic.

Conclusion

Awareness of routine vaccination schedules should be improved among health-care professionals, and reminders for immunization should be provided periodically in each health-care setting.

Vaccination Offer during the Occupational Health Surveillance Program for Healthcare Workers and Suitability to Work: An Italian Retrospective Cohort Study

The active immunization of health care workers (HCWs) is a crucial measure to avoid nosocomial infection; nevertheless, vaccine coverage (VC) among health personnel in Italy is unsatisfactory. To improve VC in the healthcare set, the Hygiene and Occupational Medicine departments of Bari Policlinico General University Hospital applied a specific program. The operative procedure demands that in the context of the occupational medical examination, all workers are evaluated for susceptibility to vaccine-preventable diseases (VDPs), with immunization prophylaxis offered to those determined to be susceptible. This study analyzed data from workers who attended the biological risk assessment protocol from December 2017 to October 2021 (n = 1477), who were evaluated for the immune status for measles, mumps, rubella, and varicella. Among the enrolled subjects, non-protective antibody titers were higher for measles and mumps (13%), followed by rubella (11%) and varicella (8%). Appropriate vaccinations were offered to all susceptible HCWs, and HCWs were re-tested one month after immunization. The seroconversion rate after the administration of one or more booster dose(s) was over 80%. Overall, 2.5% of the subjects refused the offered vaccine(s); the main determinant of immunization compliance was younger age (aOR = 0.86; 95%CI = 0.80–0.92). Especially during the COVID-19 pandemic, VPDs may still present a hazard in nosocomial environment. Our experience suggests that, despite hospital procedures and dedicated human assets, satisfactory VC cannot be reached without the provision of federal regulations. Nevertheless, public health policymakers have to improve the promotion of vaccine prophylaxis and education to reach higher VC.

Impact of influenza vaccination on GP-diagnosed COVID-19 and all-cause mortality: a Dutch cohort study

OBJECTIVES

As clinical presentation and complications of both viruses overlap, it was hypothesised that influenza vaccination was associated with lower general practitioner (GP)-diagnosed COVID-19 rates and lower all-cause mortality rates.

STUDY DESIGN

From a primary care population-based cohort in the Netherlands, GP-diagnosed COVID-19 (between 10 March and 22 November 2020) and all-cause mortality events (between 30 December 2019 and 22 November 2020) were recorded. 223 580 persons were included, representing the influenza vaccination 2019 target group (all aged ≥60 years, and those <60 years with a medical indication). Proportional hazards regression analyses evaluated associations between influenza vaccination in 2019 and two outcomes: GP-diagnosed COVID-19 and all-cause mortality. Covariables were sex, age, comorbidities and number of acute respiratory infection primary care consultations in 2019.

RESULTS

A slightly positive association (HR 1.15; 95% CI 1.08 to 1.22) was found between influenza vaccination in 2019 and GP-diagnosed COVID-19, after adjusting for covariables. A slightly protective effect for all-cause mortality rates (HR 0.90; 95% CI 0.83 to 0.97) was found for influenza vaccination, after adjusting for covariables. A subgroup analysis among GP-diagnosed COVID-19 cases showed no significant association between influenza vaccination in 2019 and all-cause mortality.

CONCLUSIONS

Our hypothesis of a possibly negative association between influenza vaccination in 2019 and GP-diagnosed COVID-19 was not confirmed as we found a slightly positive association. A slightly protective effect on all-cause mortality was found after influenza vaccination, possibly by a wider, overall protective effect on health. Future research designs should include test-confirmed COVID-19 cases and controls, adjustments for behavioural, socioeconomic and ethnic factors and validated cause-specific mortality cases.

The effect of influenza vaccine in reducing the severity of clinical outcomes in patients with COVID-19: a systematic review and meta-analysis

Recent evidence suggests that vaccination against influenza may reduce the clinical outcomes of COVID-19. This study looked at the link between influenza vaccination and the severity of COVID-19 infection. We searched five databases until August 2021. We included studies that reported the relationship between influenza vaccination and COVID-19 outcomes. We pooled the data as risk ratio (RR) or mean difference (MD), with 95% confidence intervals (CIs), the data pooled using fixed and random effects models according to the heterogeneity of results. Sixteen observational studies with 191,496 COVID-19 patients were included. In terms of mechanical ventilation, our analysis showed a significant favor for the influenza vaccinated group over the non-vaccinated group (RR = 0.72, 95% CI [0.54, 0.96], P = 0.03). However, the analysis indicated no statistically significant differences between vaccinated and non-vaccinated groups in the term of mortality rate (RR = 1.20, 95% CI [0.71, 2.04], P = 0.50), hospital admissions (RR = 1.04, 95% CI [0.84, 1.29], P = 0.75), intensive care admissions (RR = 0.84, 95% CI [0.44, 1.62], P = 0.60). There were no significant differences between those who had received the influenza vaccine and those who had not in COVID-19 clinical outcomes, except for mechanical ventilation which showed a significantly lower risk in the influenza vaccinated group compared to the non-vaccinated one. However, future research is encouraged as our data have limitations, and the influenza vaccine is regularly updated. Also, this does not exclude the importance of the influenza vaccine during the COVID-19 pandemic.

Influenza and pneumococcal vaccination and COVID-19 in kidney transplant patients

Background

This study aims to investigate the effect of recent influenza and pneumococcal vaccines' administration on the development of COVID-19 infection in kidney transplant recipients during the pandemic.

Methods

The effect of influenza and pneumococcal vaccines on the clinical course of the disease in COVID-positive (COVID group, n: 105) and COVID-negative (control group, n: 127) recipients has been examined. The control group included patients with negative rRT-PCR test results. At the time of the study, no patient was vaccinated with COVID-19 vaccine. The patients' influenza and/or pneumococcal vaccination rates in 2019 and 2020 were determined. In 2019 and 2020, 32 and 33 people in the COVID-positive group and 61 and 54 people in the COVID-negative group had received influenza and/or pneumococcal vaccines, respectively. The median study follow-up times of the COVID-negative and COVID-positive groups were 13.04 and 8.31 months, respectively.

Results

Compared with the COVID-negative group, the patients in the COVID-positive group were younger and had a longer post-transplant time. In addition, the rate of transplantation from a living donor and the rate of COVID positivity in family members were also higher. The influenza vaccination rates in the COVID negative group were significantly higher than the COVID-positive group in 2020 (23.8% vs 37%, p = 0.031). Multivariate logistic regression analysis revealed that the presence of COVID-19 in family members and lack of pneumococcal vaccination in 2020 increased the risk of being positive for COVID-19. There was no significant difference in the hospitalization rates, the need for dialysis and intensive care, the hospital stay, and the graft dysfunction in the COVID-positive patients with and without influenza and pneumococcal vaccines.

Conclusion

The observations made throughout this study suggest that influenza and pneumococcal vaccination in transplant patients may reduce the risk of COVID-19 disease and provide additional benefits during the pandemic period.

COVID-19 vaccination hesitancy in Italian healthcare workers: a systematic review and meta-analysis

INTRODUCTION

As for other vaccines, vaccination hesitancy may be a determining factor in the success (or otherwise) of the COVID-19 immunization campaign in healthcare workers (HCWs).

AREAS COVERED

To estimate the proportion of HCWs in Italy who expressed COVID-19 vaccine hesitancy, we conducted a systematic review of the relevant literature and a meta-analysis. Determinants of vaccine compliance and options suggested by these studies to address vaccine hesitancy among HCWs were also analyzed. Seventeen studies were included in the meta-analysis and systematic review, selected from scientific articles available in the MEDLINE/PubMed, Google Scholar and Scopus databases between January 1, 2020 and January 25, 2022. The vaccine hesitancy rate among HCWs was 13.1% (95%CI: 6.9-20.9%). The vaccine hesitancy rate among HCWs investigated before and during the vaccination campaign was 18.2% (95%CI=12.8-24.2%) and 8.9% (95%CI=3.4-16.6%), respectively. That main reasons for vaccine hesitation were lack of information about vaccination, opinion that the vaccine is unsafe, and fear of adverse events.

EXPERT OPINION

Despite strategies to achieve a greater willingness to immunize in this category, mandatory vaccination appears to be one of the most important measures that can guarantee the protection of HCWs and the patients they care for.

Vaccination of Elderly People Affected by Chronic Diseases: A Challenge for Public Health

Elderly people have a limited regenerative capacity and are more susceptible to disease, syndromes, injuries, and illnesses than younger adults [...]

Effect of the 2020/21 season influenza vaccine on SARS-CoV-2 infection in a cohort of Italian healthcare workers

OBJECTIVES

Healthcare workers (HCWs) are a priority group for seasonal influenza vaccination (SIV). The 2020/21 SIV campaign was conducted during the second wave of the COVID-19 pandemic. Vaccines, including SIV, may exert non-specific protective effects on other infectious diseases which may be ascribable to the concept of trained immunity. The aim of this study was to explore the association between 2020/21 SIV and SARS-CoV-2 positivity in a cohort of Italian HCWs.

METHODS

In this observational study, a cohort of HCWs employed by a large (ca 5000 employees) referral tertiary acute-care university hospital was followed up retrospectively until the start of the COVID-19 vaccination campaign. The independent variable of interest was the 2020/21 SIV uptake. Both egg-based and cell culture-derived quadrivalent SIVs were available. The study outcome was the incidence of new SARS-CoV-2 infections, as determined by RT-PCR. Multivariable Cox regression was applied in order to discern the association of interest.

RESULTS

The final cohort consisted of 2561 HCWs who underwent ≥1 RT-PCR test and accounted for a total of 94,445 person-days of observation. SIV uptake was 35.6%. During the study period, a total of 290 new SARS-CoV-2 infections occurred. The incidence of new SARS-CoV-2 was 1.62 (95% CI: 1.22-2.10) and 3.91 (95% CI: 3.43-4.45) per 1000 person-days in vaccinated and non-vaccinated HCWs, respectively, with an adjusted non-proportional hazard ratio of 0.37 (95% CI: 0.22-0.62). E-values suggested that unmeasured confounding was unlikely to explain the association.

CONCLUSIONS

A lower risk of SARS-CoV-2 infection was observed among SIV recipients.

Immune response to one dose of BNT162b2 mRNA Covid-19 vaccine followed by SARS-CoV-2 infection: An Italian prospective observational study

INTRODUCTION

A mass vaccination campaign against SARS-CoV-2 was initiated in European countries on December 27, 2020. This study compared the antibody response in a sample of healthcare workers (HCWs) who, after the first dose of the BNT162b2 mRNA vaccine, were infected with SARS-CoV-2 (infection group) with the response in a control group of HCWs immunized with two doses (vaccine group).

METHODS

This two-arm observational cohort study was carried out using routine health surveillance data obtained from HCWs at Bari Policlinico General Hospital (Italy). The antibody response was determined infection group and vaccine group.

RESULTS

Among the 100 HCWs, 25 (25.0%) were in the infection group and 75 (75.0%) in the full-vaccine group. At the serological evaluation, all of the HCWs tested positive, with a geometric mean titer (GMT) of 7106.8 (95 %CI = 5628.5-8973.4) and a statistically significant difference (p < 0.0001) between the infection group (GMT = 2139.7; 95 %CI = 1310.4-3493.6) and the vaccine group (GMT = 10603.6; 95 %CI = 8698.0-12926.8).

DISCUSSION

Our results shed light on the vaccine response of individuals in different risk categories. It also emphasizes the need for the continued use by HCWs of PPE and good practices during the window between the first and second anti-SARS-CoV-2 vaccinations.

COVID-19 and Seasonal Influenza Vaccination: Cross-Protection, Co-Administration, Combination Vaccines, and Hesitancy

SARS-CoV-2 and influenza are the main respiratory viruses for which effective vaccines are currently available. Strategies in which COVID-19 and influenza vaccines are administered simultaneously or combined into a single preparation are advantageous and may increase vaccination uptake. Here, we comprehensively review the available evidence on COVID-19/influenza vaccine co-administration and combination vaccine candidates from the standpoints of safety, immunogenicity, efficacy, policy and public acceptance. While several observational studies have shown that the trained immunity induced by influenza vaccines can protect against some COVID-19-related endpoints, it is not yet understood whether co-administration or combination vaccines can exert additive effects on relevant outcomes. In randomized controlled trials, co-administration has proved safe, with a reactogenicity profile similar to that of either vaccine administered alone. From the immunogenicity standpoint, the immune response towards four influenza strains and the SARS-CoV-2 spike protein in co-administration groups is generally non-inferior to that seen in groups receiving either vaccine alone. Several public health authorities have advocated co-administration. Different combination vaccine candidates are in (pre)-clinical development. The hesitancy towards vaccine co-administration or combination vaccines is a multifaceted phenomenon and may be higher than the acceptance of either vaccine administered separately. Public health implications are discussed.

The Potential Benefits of the Influenza Vaccination on COVID-19 Mortality Rate-A Retrospective Analysis of Patients in Poland

In this study, we used publicly available data from the Centrum e-Zdrowia (CeZ) Polish Databank proposing a possible correlation between influenza vaccination and mortality due to COVID-19. We limited our search to the patients with positive COVID-19 laboratory tests from 1 January 2020 to 31 March 2021 and who filled a prescription for any influenza vaccine during the 2019–2020 influenza season. In total, we included 116,277 patients and used a generalized linear model to analyze the data. We found out that patients aged 60+ who received an influenza vaccination have a lower probability of death caused by COVID-19 in comparison to unvaccinated, and the magnitude of this difference grows with age. For people below 60 years old, we did not observe an influence of the vaccination. Our results suggest a potential protective effect of the influenza vaccine on COVID-19 mortality of the elderly. Administration of the influenza vaccine before the influenza season would reduce the burden of increased influenza incidence, the risk of influenza and COVID-19 coinfection and render the essential medical resources accessible to cope with another wave of COVID-19. To our knowledge, this is the first study showing a correlation between influenza vaccination and the COVID-19 mortality rate in Poland.

BNT162b2 mRNA COVID-19 Vaccine Effectiveness in the Prevention of SARS-CoV-2 Infection and Symptomatic Disease in Five-Month Follow-Up: A Retrospective Cohort Study

To combat the COVID-19 pandemic, a mass vaccination campaign was initiated in Italy on 27 December 2020. The vaccine available to immunize Italian healthcare workers (HCWs) was the BNT162b2 mRNA COVID-19 vaccine (Comirnaty). This study evaluated the effectiveness of the vaccine against documented SARS-CoV-2 infection and symptomatic diseases in the medium- to long-term. HCWs at Bari Policlinico University-Hospital (Italy) who completed the vaccination schedule were matched with HCWs who had refused vaccination; the two groups were followed-up for 5 months (January-May 2021). Vaccine effectiveness (VE) against infection was 97.7% (95.4-99.0%) at 14-34 days after the first dose, and 94.8% (87.0-97.8%), 83.0% (65.0-92.0%), and 81.0% (42.0-94.0%) at 14-41, 42-69, and >69 days, respectively, after the second dose. The estimated VE for documented symptomatic disease was 99.2% (96.4-99.8%) at 14-34 days after the first dose and 97.2% (90.3-99.2%), 85.0% (63.0-94.2%), and 88.0% (42.0-97.6%) at 14-41, 42-69, and >69 days, respectively, after the second dose. Efforts to increase vaccination rates should be strengthened, including mandatory vaccination for HCWs and greater incentives to increase vaccine acceptance by the general population.

The Impact of the COVID-19 Emergency on Life Activities and Delivery of Healthcare Services in the Elderly Population

Due to the prevailing pandemic of the coronavirus disease COVID-19, we are experiencing emotional and social isolation, which negatively affects mental and physical health, particularly among the elderly population. In this study, we performed a cross-sectional analysis based on computer-assisted telephone interviews of 500 Polish adults aged 60 years or older in order to determine the impact of the SARS-CoV-2 pandemic on the older population’s behavior, life activity, and delivery of healthcare services. According to our study, COVID-19 infection entailed a substantial change in older people’s behavior. Over 50%, nearly 80%, and more than 25% of the surveyed participants reduced their social, recreational, and professional activities, respectively. The most significant change in senior’s behavior due to the fear of COVID-19 infection was observed in patients (1) with cardiac and pulmonary problems, (2) being on multi-drug therapy, (3) vaccinated against influenza, and (4) with several mental difficulties including loneliness, social isolation, and depression. Furthermore, we demonstrated that 10% of participants canceled planned hospitalization due to the fear of COVID-19 infection. This was observed primarily in patients suffering from chronic heart and lung diseases, vaccinated against influenza, exhibiting the reluctance to carry out more complex daily activities, and with a higher level of anxiety, social loneliness, and malnutrition. Thus, these groups of seniors require more attention; hence, we propose telemedicine as a strategy directed to them that provides clinical healthcare and information regarding measurements, control, and protection against SARS-CoV-2 during the prevailing COVID-19 pandemic. We believe this strategy may improve treatment outcomes, reduce comorbidities-related complications and unnecessary hospitalizations.

Examining the potential benefits of the influenza vaccine against SARS-CoV-2: A retrospective cohort analysis of 74,754 patients

INTRODUCTION

Recently, several single center studies have suggested a protective effect of the influenza vaccine against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This study utilizes a continuously updated Electronic Medical Record (EMR) network to assess the possible benefits of influenza vaccination mitigating critical adverse outcomes in SARS-CoV-2 positive patients from 56 healthcare organizations (HCOs).

METHODS

The de-identified records of 73,346,583 patients were retrospectively screened. Two cohorts of 37,377 patients, having either received or not received influenza vaccination six months-two weeks prior to SARS-CoV-2 positive diagnosis, were created using Common Procedural Terminology (CPT) and logical observation identifiers names and codes (LOINC) codes. Adverse outcomes within 30, 60, 90, and 120 days of positive SARS-CoV-2 diagnosis were compared between cohorts. Outcomes were assessed with stringent propensity score matching including age, race, ethnicity, gender, hypertension, diabetes, hyperlipidemia, chronic obstructive pulmonary disease (COPD), obesity, heart disease, and lifestyle habits such as smoking.

RESULTS

SARS-CoV-2-positive patients who received the influenza vaccine experienced decreased sepsis (p<0.01, Risk Ratio: 1.361-1.450, 95% CI:1.123-1.699, NNT:286) and stroke (p<0.02, RR: 1.451-1.580, 95% CI:1.075-2.034, NNT:625) across all time points. ICU admissions were lower in SARS-CoV-2-positive patients receiving the influenza vaccine at 30, 90, and 120 days (p<0.03, RR: 1.174-1.200, 95% CI:1.003-1.385, NNT:435), while approaching significance at 60 days (p = 0.0509, RR: 1.156, 95% CI:0.999-1.338). Patients who received the influenza vaccine experienced fewer DVTs 60-120 days after positive SARS-CoV-2 diagnosis (p<0.02, RR:1.41-1.530, 95% CI:1.082-2.076, NNT:1000) and experienced fewer emergency department (ED) visits 90-120 days post SARS-CoV-2-positive diagnosis (p<0.01, RR:1.204-1.580, 95% CI: 1.050-1.476, NNT:176).

CONCLUSION

Our analysis outlines the potential protective effect of influenza vaccination in SARS-CoV-2-positive patients against adverse outcomes within 30, 60, 90, and 120 days of a positive diagnosis. Significant findings favoring influenza vaccination mitigating the risks of sepsis, stroke, deep vein thrombosis (DVT), emergency department (ED) & Intensive Care Unit (ICU) admissions suggest a potential protective effect that could benefit populations without readily available access to SARS-CoV-2 vaccination. Thus further investigation with future prospective studies is warranted.