Immunization Of Healthcare Workers Research Articles

Durability of COVID-19 humoral immunity post infection and different SARS-COV-2 vaccines

BackgroundThe global challenge posed by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has been a major concern for the healthcare sector in recent years. Healthcare workers have a relatively high risk of encountering COVID-19 patients, making protective immunity against SARS-CoV-2 is a priority for them. This study aims to evaluate the longitudinal measurement of SARS-CoV-2 IgG spike protein antibodies in healthcare workers (HCWs) after COVID-19 infection and after receiving the first and second doses of SARS-CoV-2 vaccines, including Pfizer-BioNTech (BNT162b2) and Oxford-AstraZeneca (AZD1222). MethodsThis longitudinal cohort study involved 311 healthcare workers working in two tertiary hospitals in Saudi Arabia. All participants were followed between July 2020 and July 2022 after completing the study questionnaire. A total of 3 ml of the blood samples were collected at four intervals: before/after vaccination. ResultsHCWs post-infection had lower mean SARS-CoV-2 IgG levels three months post-infection than post-vaccination. 92.2% had positive IgG levels two weeks after the first dose and reached 100% after the second dose. Over 98% had positive antibodies nine months after the second dose, regardless of vaccine type. The number of neutralizing antibodies decreased and was around 50% at nine months after the second dose. ConclusionThe results show different antibody patterns between infected and vaccinated HCWs. A high proportion of participants had positive antibodies after vaccination, with high levels persisting nine months after the second dose. Neutralizing antibodies decreased over time, with only about 50% of participants having positive antibodies nine months after the second dose. These results contribute to our understanding of immunity in healthcare workers and highlight the need for the continuous monitoring and possible booster strategies.

Seroprevalence for measles among healthcare workers in Madrid, Spain

Immunity of healthcare workers (HCWs) against measles is a particular concern. They are more likely to contract it than the general population due to their occupational exposure which may cause a nosocomial outbreak. To assess the measles immune status of HCWs at five Spanish university hospitals. Serologic testing (IgG) for measles by chemiluminescence indirect immunoassay (CLIA) was carried out prospectively and consecutively in HCWs from five university hospitals. All HCWs were classified into four epidemiological groups: vaccinated individuals, those with a history of measles disease, subjects with no history of measles or vaccination, and those who did not know whether they had measles or were vaccinated, and into five professional categories: physicians, nurses, nursing assistants, other clinical workers and non-clinical workers. A logistic regression model was constructed to identify the factors independently associated with immunity to measles. The study group was composed of 2157 HCWs. 89% had protective antibodies against measles. Of the 238 non-immune HCWs, 199 (83.6%) had been vaccinated, compared with 1084 of the 1919 (56.5%) immune individuals (P<0.0001). The parameters significantly predictive of having protective antibodies against measles were: older age (P<0.0001), epidemiological status (P=0.0002, mainly past measles disease), and professional category (P=0.02, in particular nurses). This study shows that HCWs, including those previously vaccinated, are currently at risk of measles and suggests that those with a natural history of infection are better protected. Therefore, knowledge and maintenance of immunity to measles are an essential part of infection control among HCWs.

Examining the Effect of SARS-CoV-2 Pandemic-Induced Stress and Anxiety on Humoral Immunity in Health Care Workers.

The effect of stress on vaccine-induced humoral immunity and therapeutic interventions to mitigate pandemic-related stress remain underexplored. Participants in a longitudinal cohort study ( n = 189) completed a validated measure, GAD-7, and 10-instrument stress measure to assess stress and anxiety after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. Serum was collected to obtain SARS-CoV-2 antibody titer levels. Participants experienced increased stress due to the SARS-CoV-2 pandemic with a positive correlation between GAD-7 scores and peak antibody titers overall; however, there was a negative association with scores commensurate with severe anxiety. Health care workers and younger participants were more significantly affected by anxiety. Mild anxiety levels may have immune-enhancing effects, whereas severe anxiety may cause antibody generation reduction. Mental health-focused interventions are imperative for younger adults and health care workers. Young adults may be more resilient to increased stress levels.

Mucosal humoral immune response of respiratory tract in medical workers during the post-COVID-19 period

Currently, the role of local respiratory tract immunoglobulins in COVID-19 and rearrangement of mucosal immune response in the post-COVID period have not been sufficiently studied. Our aim was to evaluate long-term effects of novel coronavirus infection on the mucosal immunity in healthcare workers over the post-infection period.&#x0D; A total of 180 healthcare workers, ranging in age from 18 to 65 years, were enrolled in a one-stage, cross-sectional study. The subjects with a history of COVID-19 were divided into three groups, depending on the severity of their disease. The control group consisted of 44 healthcare workers who had no history of novel coronavirus infection. Secretory immunoglobulin A (sIgA) and total immunoglobulin G (IgG) levels were quantified in saliva samples, induced sputum samples, naso- and oropharyngeal scrapings by ELISA technique. Specific anti-SARS-CoV-2 IgG antibodies were quantified in the serum by chemiluminescence immunoassay.&#x0D; Numerous shifts in adaptive immune response were detected for different mucosal compartments, i.e., in subjects who suffered from severe or moderate-to-severe COVID-19, salivary sIgA levels were significantly higher than those in the control group (p 0.05 and p 0.005, respectively). An inverse correlation was demonstrated between the levels of total sIgA in all mucosal sites, and the number of days from the onset of disease to the start of study (r = 0.278, р 0.05). When compared to the control subjects, all the patients with prior COVID-19 had significantly higher levels of total IgG in the induced sputum samples. Total IgG in saliva was also higher in the group of patients who had severe infection (p 0.05). By contrast, IgG levels in nasopharyngeal samples were decreased in severe and moderately severe groups compared to the control group, thus, probably, indicating an immunodeficiency state in these cases. A direct significant correlation was also detected between the levels of total IgG in all studied samples and the levels of specific IgG antibodies against SARS-CoV-2 in the serum.&#x0D; Long-term changes in the humoral mucosal immune response were most pronounced in the healthcare workers with a history of severe or moderate-to-severe COVID-19.

HEALTHCARE WORKERS IN BULGARIA - ARE THEY PROTECTED FROM VACCINE-PREVENTABLE INFECTIONS?

Background: Healthcare workers (HCWs) are at increased risk of exposure to many viral infections, including vaccine preventable diseases (VPDs) such as measles, mumps and rubella (MMR) as compared to non-HCWs. Immunity of HCWs against these viruses is mandatory in a healthcare setting due to possible exposure from patients or colleagues. Aim: To provide an assessment of anti-measles, mumps and rubella IgG seropositivity among Bulgarian HCWs employed in hospitals and regional health inspectorates (RHI), as an indicator of protective immunity against MMR in this risk group. Materials and Methods: In the current study, 181 HCWs from Infectious Units in regional hospitals in the country, and HCWs from the RHI, involved in the monitoring and surveillance of MMR cases in Bulgaria were screened. Serum specimens from all participants were tested by a commercial indirect enzyme-linked immunosorbent assay (Anti-Measles, Anti-Mumps, Anti-Rubella IgG EIA-Euroimmun®, Germany) for presence of IgG antibodies against measles, mumps and rubella, as an indicator of protective immunity. Results: The study included 181 HCWs, 25 male and 156 female, aged 22 to 66 years. The average protective seroprevalence for measles, mumps and rubella was 82.9%, 76.2% and 92.3% percent, respectively. The highest share of negative results were obtained for mumps-specific IgG – 23.2% (42/181), followed by measles 16.6% (60/181) and rubella-specific IgG 7.7% (19/181). Regarding the age distribution, the highest number of HCWs non-immune to measles and mumps was found among the 31- 40-year olds, and against mumps – among the 41-50-year-olds. Conclusion: HCWs are at greater risk of contracting infections than the general population because of contact with sick patients or infectious material. Infected healthcare workers can spread nosocomial diseases to vulnerable patients with more severe illness, leading to complications and even death. Therefore, the vaccination status of HCWs must be strictly monitored.

Mucosal immunity in health care workers’ respiratory tracts in the post-COVID-19 period

Coronavirus disease (COVID-19) has generated interest in the assessment of systemic immune status, but existing knowledge about mucosal immunity is clearly insufficient to understand the full pathogenetic mechanisms of the disease. The aim of this study was to evaluate the long-term effects of novel coronavirus infection on mucosal immunity in the postinfection period among health care workers (HCWs). A total of 180 health care workers with and without a history of COVID-19 who ranged in age from 18 to 65 years were enrolled in this one-stage, cross-sectional study. The study subjects completed the 36-Item Short Form (36) Health Survey (SF-36) and the Fatigue Assessment Scale. Secretory immunoglobulin A (sIgA) and total immunoglobulin G (IgG) levels were quantified in saliva samples, induced sputum samples, and nasopharyngeal and oropharyngeal scrapings by an enzyme-linked immunosorbent assay. Specific anti-SARS-CoV-2 IgG antibodies were quantified in serum samples by chemiluminescence immunoassay. Analysis of the questionnaire data showed that all HCWs with a history of COVID-19 reported health problems that limited their daily activities and negative changes in their emotional health three months after the disease, regardless of its severity. The following shifts were detected in the adaptive arm of the immune response in different mucosal compartments. Among subjects who had severe or moderate-to-severe COVID-19, salivary sIgA levels were significantly higher than those in the control group (p < 0.05 and p < 0.005, respectively). Compared to the subjects in the control group, all subjects with prior COVID-19 had significantly higher levels of total IgG in induced sputum. In the group of patients who had had severe infection, total IgG in saliva was also higher (p < 0.05). A direct statistically significant correlation was also detected between the levels of total IgG in all studied samples and the levels of specific IgG antibodies against SARS-CoV-2 in the serum. A significant correlation was observed between total IgG levels and the parameters of physical and social activities, mental health, and fatigue levels. Our study demonstrated long-term changes in the humoral mucosal immune response, which were most pronounced in health care workers with a history of severe or moderate-to-severe COVID-19, and an association of these changes with certain clinical signs of post-COVID-19 syndrome.

Measles Immunization Status of Health Care Workers: A Cross-Sectional Study Exploring Factors Associated with Lack of Immunization According to the Health Belief Model.

Suboptimal levels of measles vaccination coverage make Italy a country where the circulation of the virus is still endemic. In the past decade, several nosocomial outbreaks of measles occurred in Italy that rapidly spread the infection among large numbers of hospitalized patients and susceptible healthcare workers (HCWs). A cross-sectional study was conducted at the University Hospital of Palermo (Italy) to estimate the rate of HCWs immunization and to investigate the factors associated with lack of immunization. The attitude to the immunization practice was evaluated by exploring the Health Belief Model. Overall, 118 HCWs were enrolled, with a mean age of 31 years and 59.3% male. About half of the sample (45.8%, n = 54) was found not to be immunized against measles. Multivariable analysis showed that the factors directly associated with the non-immunization status against measles were female sex (OR = 3.70, p = 0.056), being an HCW different from a physician (OR = 10.27, p = 0.015), having a high perception of barriers to vaccination (OR = 5.13, p = 0.047), not being immunized for other exanthematous diseases such as chickenpox (OR = 9.93, p = 0.003), mumps (OR = 33.64, p < 0.001) and rubella (OR = 10.12, p= 0.002). There is a need to contrast the low adherence of HCWs to measles vaccination by identifying effective strategies to increase immunization coverage and limiting the risk of further nosocomial measles outbreaks.

Evolution of long-term vaccine-induced and hybrid immunity in healthcare workers after different COVID-19 vaccine regimens.

Both infection and vaccination, alone or in combination, generate antibody and Tcell responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the maintenance of such responses-and hence protection from disease-requires careful characterization. In a large prospective study of UK healthcare workers (HCWs) (Protective Immunity from T Cells in Healthcare Workers [PITCH], within the larger SARS-CoV-2 Immunity and Reinfection Evaluation [SIREN] study), we previously observed that prior infection strongly affected subsequent cellular and humoral immunity induced after long and short dosing intervals of BNT162b2 (Pfizer/BioNTech) vaccination. Here, we report longer follow-up of 684 HCWs in this cohort over 6-9months following two doses of BNT162b2 or AZD1222 (Oxford/AstraZeneca) vaccination and up to 6months following a subsequent mRNA booster vaccination. We make three observations: first, the dynamics of humoral and cellular responses differ; binding and neutralizing antibodies declined, whereas T and memory B cell responses were maintained after the second vaccine dose. Second, vaccine boosting restored immunoglobulin (Ig) G levels; broadened neutralizing activity against variants of concern, including Omicron BA.1, BA.2, and BA.5; and boosted Tcell responses above the 6-month level after dose 2. Third, prior infection maintained its impact driving larger and broader Tcell responses compared with never-infected people, a feature maintained until 6months after the third dose. Broadly cross-reactive Tcell responses are well maintained over time-especially in those with combined vaccine and infection-induced immunity ("hybrid" immunity)-and may contribute to continued protection against severe disease. Department for Health and Social Care, Medical Research Council.

Evaluation of ichroma™ COVID-19 interferon gamma release assay for detection of vaccine-induced immunity in healthcare workers

We compared the performance of a new interferon gamma release assay (IGRA) format assay, the ichroma™ COVID-19 IGRA (IGRA-SARS), with that of thewidely used QuantiFERON SARS-CoV-2 ELISA kit (QFN-SARS) in vaccinated healthcare workers (HCWs). Additionally, we analyzed the long-term changes in IGRA results after the final vaccine dose. A total of 383 specimens from 281 HCWs were enrolled in this study, and the results of SARS-IGRA andQFN-SARS assays were compared. In addition, we performed the receive operator curve analysis to estimate the optimal cut-off value for IGRA-SARS. For all specimens, IGRA-SARS and QFN-SARS showed 75.7% and 64.2% of the positive results, respectively. The absolute agreement between IGRA-SARS and QFN-SARS was 80.0%, and the Fleiss' κ value was 0.525, indicating moderate agreement. ROC curve analysis of the IGRA-SARS results showed a cut-off value of >0.254IU/mL, which was consistent with the manufacturer's specifications. The positive rates of both IGRA assays decreased significantly after a postvaccination period of 6months. IGRA-SARS showed acceptable performance in the detection of vaccine-induced immunity against COVID-19; however, harmonization of IGRA assays has notyet been achieved. Additionally, the significant decline of positive rates of IGRA after the last vaccination wouldsupport the necessity of booster vaccination after a postvaccination period of 6months.

Seroprevalence of Varicella-Zoster Virus and Measles among Healthcare Workers in a Tertiary Medical Center in Korea.

Measles and varicella still occur in the general population despite the widespread vaccination against them, and healthcare workers (HCWs) are still at risk of exposure to these diseases. Here, we evaluated the seroprevalence of measles and varicella-zoster virus (VZV) in HCWs and the trend of seroprevalence according to age, birth year, and occupational group. The serostatuses of measles and VZV of HCWs during new employee medical examinations between October 2015 and October 2021 were included. Thereafter, the trends of seroprevalence according to age, birth year, and occupational groups were evaluated. Overall, 2070 and 1827 HCWs were evaluated for VZV and measles serostatus, respectively. The seroprevalences of VZV and measles were 91% (1884/2070) and 70% (1284/1827), respectively. Younger HCWs had a significantly lower seroprevalence of measles (p = 0.02, age) and VZV (p = 0.003, birth year and p &lt; 0.001, age). The seroprevalence of measles and VZV was significantly higher among doctors and nursing assistants than among nurses and other HCWs (p &lt; 0.001 in both). In conclusion, the seroprevalence of measles and VZV significantly decreased in younger HCWs. Additionally, monitoring the serostatus of measles and VZV and the immunization of susceptible HCWs are required to prepare and control infectious diseases in healthcare facilities.

COVID-19 Vaccine Uptake among Healthcare Workers: A Systematic Review and Meta-Analysis.

The vaccine-induced immunity of healthcare workers (HCWs) is crucial to controlling the COVID-19 pandemic. Therefore, we conducted a systematic review and meta-analysis to assess the COVID-19 vaccine uptake among HCWs worldwide and to identify predictors of vaccination. We searched Scopus, Web of Science, Medline, PubMed, ProQuest, CINAHL, and medRxiv up to 25 August 2022. We applied the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. We found 25 studies including 491,624 vaccinated HCWs, while the full sample included 555,561 HCWs. The overall proportion of vaccinated HCWs was 77.3%. Vaccine uptake for studies that were conducted in North America (85.6%) was higher than the proportion for studies that were conducted in Asia (79.5%), Europe (72.8%), and Africa (65.6%). The overall prevalence of COVID-19 vaccine uptake was 83.6% and 77.4% for physicians and nurses, respectively. Older age, white race, physicians’ profession, seasonal influenza vaccine, direct COVID-19 patient care, and confidence in COVID-19 vaccine safety and effectiveness were positive predictors of vaccine uptake, while history of SARS-CoV-2 infection was a negative predictor. Deep understanding of the factors that influence HCWs’ decisions to receive a COVID-19 vaccine is critical to implementing tailored communication strategies for HCWs who are at risk for not getting vaccinated.

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.

Healthcare workers’ acceptability of influenza vaccination nudges: Evaluation of a real-world intervention

Nudges have been proposed as an effective tool to stimulate influenza vaccination uptake in healthcare workers. However, the success of such nudges in practice is heavily reliant on their acceptance by the intended healthcare worker population, which has not been thoroughly examined to date. This study investigated healthcare workers’ acceptability of diverse influenza vaccination nudges implemented in a real-world vaccination campaign and explored the relationship between nudge acceptability and vaccination uptake. A cross-sectional study was conducted among 244 Dutch hospital employees, following a hospital-wide influenza vaccination nudging intervention. A survey assessed healthcare workers’ perceived acceptability of ten distinct influenza vaccination nudges, along with their vaccination status and relevant covariates (e.g., general perceptions regarding influenza vaccination of healthcare workers). Influenza vaccination nudges in general were deemed acceptable, with reward-based nudges being the least accepted, while digital vaccination forms, a mobile vaccination post, peer vaccination, and digital vaccination reminders were most appreciated. A higher overall acceptance of these nudges was associated with a greater likelihood of being vaccinated, particularly in healthcare workers with favorable perceptions of influenza vaccination usefulness. Our findings suggest that influenza vaccination nudges are an accepted means to systematically promote immunization of healthcare workers, and thus present a viable strategy for public health policies aimed at this group.

Comparison of the Immunogenicity and Protective Efficacy of Various SARS-CoV-2 Vaccines among Healthcare Workers: Are Our White Coat Armies Protected?

Background: The effective immunization of healthcare workers (HCWs) plays a vital role in preventing the spread of SARS-CoV-2 infection during the coronavirus disease 2019 (COVID-19) pandemic. There is limited data on the immune response to vaccination among HCWs. We aim to determine seroprevalence rates and neutralizing IgG antibody response to various immunizations among HCWs. Methods: This study was conducted between July and September 2021, in which blood samples were obtained from HCWs and SARS-CoV-2 IgG neutralizing antibodies were measured. Data regarding vaccination status with Pfizer/BioNTech, Sinopharm, or AstraZeneca vaccines, occupation, and prior COVID-19 infection were analyzed. Results: COVID-19 infection post-vaccination was associated with higher mean antibody titers, regardless of vaccine type. Pfizer/BioNTech vaccination produced higher mean antibody titers for HCWs with prior COVID-19 infection (p < 0.00001) than other types of vaccines. Although 96% of HCWs were vaccinated, 3% were seronegative. For HCWs who were seropositive, there were no significant differences between the mean antibody titers when comparing occupations and blood indices. Conclusion: Awareness of the immunity status of HCWs is key to protecting this important group against SARS-CoV-2, especially those without prior COVID-19 infection. Further public health efforts regarding booster vaccination for HCWs are crucial to provide necessary antibody protection.

Predictors of impaired SARS-CoV-2 immunity in healthcare workers after vaccination with BNT162b2

Healthcare workers are at substantially increased risk for infection with SARS-CoV-2. Successful vaccination constitutes a crucial prerequisite to protect this group during the pandemic. Since post vaccination antibody monitoring is not standard of care in all healthcare institutions, data on risk factors of impaired vaccine induced immune response are urgently required. Moreover, there are no data on cellular immune responses in humoral low responders so far. Anti-SARS-CoV-2 spike IgG was assessed after vaccination with BNT162b2 in 1386 employees of three hospitals of a German healthcare provider. Concentrations were compared to those of 45 convalescent employees. Vaccine-induced cellular immunity was measured in employees with reduced humoral response by assessment of frequencies of SARS-CoV-2-reactive CD4+ and CD8+ T cell. Anti-SARS-CoV-2 spike IgG were detected in 99.9% of 1386 healthcare workers after completed vaccination. The median antibody concentration was significantly higher after vaccination than after infection with SARS-CoV-2 (p = 0.0001). 10 subjects (0.7%) generated an IgG concentration < 100 IU/ml, and only two persons (0.1%, solid organ recipients) did not produce detectable antibodies at all. T cell responses of those subjects with submaximal or lacking humoral response were comparable to employees with maximal antibody titers. 50% of those individuals with impaired or lacking humoral immune response were on immunosuppression. Vaccination to SARS-CoV-2 with BNT162b2 is very effective in healthcare workers yielding a seroconversion rate of 99.9%. Immunosuppression is the most important risk factor of an impaired immune response. There was no case of vaccination failure without immunosuppression. Thus, post vaccination antibody monitoring is highly recommendable in those employees with immunosuppression.

Comparison of measles incidence in different age groups with the intensity of specific humoral immunity in healthcare workers in Moscow

The study of the intensity of humoral immunity to the measles virus (Paramyxoviridae: Morbillivirus) (MV) remains relevant due to the ongoing registration of the cluster cases of measles (including nosocomial cases).The aim of the study was to analyze correlation between the intensity of the humoral immunity to measles virus and the measles incidence in different age groups of the Moscow residents. A simple analytic study was carried out under the framework of measles prevention improvement program conducted in the subjects of the Russian Federation. The study included the analysis of the reasons for the increase in the proportion of seronegative individuals and the comparison of the results of seromonitoring with the data of age-related measles incidence. Throughout 2018, total 1,855 blood serum samples obtained from employees of a large hospital center in Moscow who were previously vaccinated against measles were tested for IgG antibodies (ABs) to MV. The subjects were divided into 11 groups according to their age. Statistical analysis of the obtained data was performed using nonparametric criteria. The proportion of seronegative individuals among the staff of the medical facility decreased with age, from 38.5% in persons aged 19-23 to 0% among employees aged 64 and over. Persons aged 19-43 years were the most susceptible to measles infection, which was confirmed also by the highest incidence rate at these age groups (from 6.93 to 14.03 per 100,000 population). The age group most protected against measles was those over 64 years of age, who were all seropositive and had the lowest rates of incidence. This is probably due to the fact that by this age most of them have had a measles infection and have formed a sufficient immune response. At the same time, younger individuals living in the post-elimination era have only vaccine-induced ABs to MV, the level of which declines rapidly to non-protective values in the absence of boosterization due to the exposure to the wild-type strain of the pathogen. The monitoring of the MV-specific IgG- AB levels is required for employees in the medical institutions under the age of 35. Administration of the single dose of the appropriate vaccine is recommended for seronegative individuals.

Reduced T Cell and Antibody Responses to Inactivated Coronavirus Vaccine Among Individuals Above 55 Years Old.

CoronaVac is an inactivated SARS-CoV-2 vaccine that has been rolled out in several low and middle-income countries including Brazil, where it was the mainstay of the first wave of immunization of healthcare workers and the elderly population. We aimed to assess the T cell and antibody responses of vaccinated individuals as compared to convalescent patients. We detected IgG against SARS-CoV-2 antigens, neutralizing antibodies against the reference Wuhan SARS-CoV-2 strain and used SARS-CoV-2 peptides to detect IFN-g and IL-2 specific T cell responses in a group of CoronaVac vaccinated individuals (N = 101) and convalescent (N = 72) individuals. The frequency among vaccinated individuals, of whom 96% displayed T cell and/or antibody responses to SARS-CoV-2, is comparable to 98.5% responses of convalescent individuals. We observed that among vaccinated individuals, men and individuals 55 years or older developed significantly lower anti-RBD, anti-NP and neutralization titers against the Wuhan strain and antigen-induced IL-2 production by T cells. Neutralizing antibody responses for Gamma variant were even lower than for the Wuhan strain. Even though some studies indicated CoronaVac helped reduce mortality among elderly people, considering the appearance of novel variants of concern, CoronaVac vaccinated individuals above 55 years old are likely to benefit from a heterologous third dose/booster vaccine to increase immune response and likely protection.

Assessing humoral immune response after two doses of an inactivated SARS-CoV-2 vaccine (CoronaVac) in healthcare workers

ObjectivesDuring COVID-19 pandemic, the absence of immunity in the population left them susceptible to infection with SARS-CoV-2; healthcare workers (HCWs) being in the highest risk group. This study intends to assess and follow up the humoral immunity in HCWs vaccinated with an inactive virus vaccine (CoronaVac). Study designThis is a prospective observational study. MethodsA total of 1072 HCWs were investigated for the presence of immunoglobulin G antibodies to the receptor-binding domain of the S1 subunit of the spike protein of SARS-CoV-2 after vaccination. Blood samples were obtained after 28 days of the first dose, 21 days of the second dose, and 3 months after the second dose. Detection of antispike antibodies was performed by the chemiluminescent microparticle immunoassay method (SARS-CoV-2 IgG II Quant, Abbott, Ireland). The results greater than or equal to the cutoff value of 50.0 AU/mL were reported as positive. ResultsFour weeks after the first dose of vaccine, antispike antibodies were detected in 834/1072 (77.8%) of HCWs. Seropositivity was higher among females (84.6%) than males (70.6% p < 0.001) and was found to be highest in both women and men between the ages of 18–34 years. Antispike antibodies were detected in 1008 of 1012 (99.6%) after 21 days of the second dose and in 803 of 836 (96.1%) after 3 months of the second dose. ConclusionsCoronaVac was found to be highly immunogenic after two consecutive doses performed 28 days apart to HCWs; however, the immunogenicity declined significantly (p < 0.001) after 3 months following the second dose of vaccine.

Evolution of Long-Term Hybrid Immunity in Healthcare Workers after Different Covid-19 Vaccination Regimens: A Longitudinal Observational Cohort Study

Evolution of Long-Term Hybrid Immunity in Healthcare Workers after Different Covid-19 Vaccination Regimens: A Longitudinal Observational Cohort Study

Association of clinical and epidemiological characteristics with COVID-19 BNT162b2 mRNA vaccine short-term adverse reactions in healthcare workers

ABSTRACT Introduction The aim of the study was to investigate the prevalence and severity of adverse reactions (ARs) after immunization of healthcare workers (HCWs) with BNT162b2 vaccine and to associate them with clinical and epidemiological characteristics. Methods A form containing demographic and clinical data as well as ARs after both doses of the vaccine was completed, and statistical association analysis was performed. Results A total of 502 HCWs (females 78.3%) with mean age (±SD) 48.17 years (±12.97) participated. After the first dose, 404 (80.5%) HCWs reported at least one local AR (LAR) and 366 (72.9%) after the second dose (p-value=0.004). After the first dose, 121 (24.1%) HCWs reported at least one systemic AR (SAR) and 275 (54.8%) after the second dose (p-value<0.0001). In the logistic regression analysis, there was no association of gender or medical history of underlying disease with LARs. There was a negative association of age with the cumulative score (CS) of LARs (OR: 0.82, 95% CI: 0.69–0.96) after the first dose. Females had a positive association with CS of SARs following both doses (OR, 95% CI: 2.57, 1.39–4.73 and 2.71, 1.76–4.19, respectively). Age was negatively associated with CS of SARs (OR: 0.66, 95% CI: 0.57–0.76) after the second dose. Severe ARs included Bell’s palsy (1) and tinnitus with temporary hearing loss (1). Conclusion The administration of the BNT162b2 vaccine in our HCWs cohort had a good safety profile with the most common ARs being self-limited. An increasing rate of SARs following the second vaccine dose was noticed. Rare but severe possible ARs should be further investigated.