Antibodies In 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.

Prevalence of neutralizing antibodies against SARS-CoV-2 using a rapid serological test in health workers of a Spanish Department of Health in Alicante (Spain) before the booster dose of the vaccine

AimTo study the prevalence of neutralizing antibodies in healthcare workers and healthcare support personnel after the administration of the second dose of the BNT162b2 vaccine (Pfizer-BioNTech). Materials and MethodsIn December 2021, we undertook a study in the Health Department in Orihuela, Alicante (Spain), which consists of 1500 workers. We collected demographic variables about the study participants, and we performed a “point-of-care” immunochromatography test to measure the presence of neutralizing antibodies (OJABIO® SARS-CoV-2 Neutralizing Antibody Detection Kit, manufactured by Wenzhou OJA Biotechnology Co., Ltd. Wenzhou, Zhejiang, China) before the administration of the third dose of the vaccine. ResultsWe obtained complete information about 964 (64%) workers, which consisted of 290 men and 674 women. The average age was 45,8 years (min. 18, max. 68) and the average time since the last dose of the vaccine was 40,5 weeks (min. 1,71, max. 47,71). A total of 131 participants (13,5%) had suffered infection by SARS-CoV-2 confirmed using RT-PCR. The proportion of participants who showed presence of neutralizing antibodies was 38,5%. In the multivariable analysis, the time since the last dose of the vaccine (aOR week: 1,07; 95%CI: 1,04; 1,09) and previous infection by SARS-CoV-2 (aOR: 3,7; 95CI: 2,39; 5,63) showed a statistically significant association with the presence of neutralizing antibodies. ConclusionsThe time since the administration of the last dose of the vaccine and the previous infection by SARS-CoV-2 determined the presence of neutralizing antibodies in 38,5% of the healthcare workers and support workers.

High seroprevalence of SARS-CoV-2 antibodies in healthcare workers in COVID-19 wards indicates an occupational hazard-a prospective cohort study during the first year of the COVID-19 pandemic in Kalmar County, Sweden.

The aim of this study is to report the seroprevalence of SARS-CoV-2 antibodies in healthcare workers with various risk of occupational exposure in Kalmar County, Sweden, during the first year of the coronavirus disease 2019 (COVID-19) pandemic. We performed SARS-CoV-2 antibody measurements at four time points, from May 2020 to May 2021, in 401 healthcare workers (HCW) at seven hospital wards and two residential care facilities, with different risk of SARS-CoV-2 exposure. Overall, the prevalence of SARS-CoV-2 antibodies in HCW in Kalmar County was high compared to similar studies from other countries and increased from May 2020 to May 2021. Initially, 14% of the participants were SARS-CoV-2 seropositive. This number increased to 18% in September and 21% in December 2020. In May 2021, the prevalence of antibodies to nucleocapsid antigen had increased to 28%, while antibodies to spike protein had increased to 95% due to vaccination. A large variation in seroprevalence between different wards was detected and HCW in a COVID-19 designated ward had significantly higher seroprevalence than HCW working in wards without COVID-19 patients, with a risk ratio of 7.28, (95% CI 2.38-22.33) in May 2020. Our findings suggest a relationship between occupational COVID-19 exposure and seropositivity which implies that efficient hygiene routines for health- and social care workers are essential to avoid that COVID-19 care will constitute an occupational hazard.

King Salman Humanitarian Aid and Relief Centre (KSrelief) During the COVID-19 Crisis and its Impact on the Seroprevalence of COVID-19 Antibodies in Healthcare Workers in Yemen

King Salman Humanitarian Aid and Relief Centre (KSrelief) During the COVID-19 Crisis and its Impact on the Seroprevalence of COVID-19 Antibodies in Healthcare Workers in Yemen

Comparison of the prevalence of SARS-CoV-2 nucleoprotein antibodies in healthcare workers and an unselected adult and paediatric all-comer patient population: insights from a longitudinal study of healthcare workers and concurrent serial cross-sectional studies of patients at an academic medical centre in Austria

ObjectivesThis study aimed to estimate and compare the prevalence of the virus-specific antibodies against the SARS-CoV-2 nucleoprotein antigen (anti-SARS-CoV-2 N) in healthcare workers and an all-comer paediatric and adult patient...

A prospective study of risk factors associated with seroprevalence of SARS-CoV-2 antibodies in healthcare workers at a large UK teaching hospital

ObjectivesTo describe the risk factors for SARS-CoV-2 infection in UK healthcare workers (HCWs). MethodsWe conducted a prospective sero-epidemiological study of HCWs at a major UK teaching hospital using a SARS-CoV-2 immunoassay. Risk factors for seropositivity were analysed using multivariate logistic regression. Results410/5,698 (7·2%) staff tested positive for SARS-CoV-2 antibodies. Seroprevalence was higher in those working in designated COVID-19 areas compared with other areas (9·47% versus 6·16%) Healthcare assistants (aOR 2·06 [95%CI 1·14-3·71]; p=0·016) and domestic and portering staff (aOR 3·45 [95% CI 1·07-11·42]; p=0·039) had significantly higher seroprevalence than other staff groups after adjusting for age, sex, ethnicity and COVID-19 working location. Staff working in acute medicine and medical sub-specialities were also at higher risk (aOR 2·07 [95% CI 1·31-3·25]; p<0·002). Staff from Black, Asian and minority ethnic (BAME) backgrounds had an aOR of 1·65 (95% CI 1·32 – 2·07; p<0·001) compared to white staff; this increased risk was independent of COVID-19 area working. The only symptoms significantly associated with seropositivity in a multivariable model were loss of sense of taste or smell, fever, and myalgia; 31% of staff testing positive reported no prior symptoms. ConclusionsRisk of SARS-CoV-2 infection amongst HCWs is highly heterogeneous and influenced by COVID-19 working location, role, age and ethnicity. Increased risk amongst BAME staff cannot be accounted for solely by occupational factors.

SARS-CoV-2 Seroprevalence among Healthcare Workers after the First and Second Pandemic Waves.

Background: The Grand Hôpital de Charleroi is a large non-academic Belgian hospital that treated a large number of COVID-19 inpatients. In the context of this pandemic, all professions-combined healthcare workers (HCWs), and not only direct caregivers, are a frontline workforce in contact with suspected and confirmed COVID-19 cases and seem to be a high-risk group for exposure. The aim of our study was to estimate the prevalence of anti-SARS-CoV-2 antibodies in HCWs in our hospital after the first and second pandemic waves and to characterize the distribution of this seroprevalence in relation to various criteria. Methods: At the end of the two recruitment periods, a total of 4008 serological tests were performed in this single-center cross-sectional study. After completing a questionnaire including demographic and personal data, possible previous COVID-19 diagnostic test results and/or the presence of symptoms potentially related to COVID-19, the study participants underwent blood sampling and serological testing using DiaSorin’s LIAISON® SARS-CoV-2 S1/S2 IgG test for the first phase and LIAISON® SARS-CoV-2 TrimericS IgG test for the second phase of this study. Results: In total, 302 study participants (10.72%) in the first round of the study and 404 (33.92%) in the second round were positive for SARS-CoV-2-IgG antibodies. The prevalence of seropositivity observed after the second wave was 3.16 times higher than after the first wave. We confirmed that direct, prolonged, and repeated contact with patients or their environment was a predominant seroconversion factor, but more unexpectedly, that this was the case for all HCWs and not only caregivers. Finally, the notion of high-risk contact seemed more readily identifiable in one’s workplace than in one’s private life. Conclusions: Our study confirmed that HCWs are at a significantly higher risk of contracting COVID-19 than the general population, and suggests that repeated contacts with at-risk patients, regardless of the HCWs’ professions, represents the most important risk factor for seroconversion (Clinicaltrials.gov number, NCT04723290).

Humoral Immune Response Induced by the BBIBP-CorV Vaccine (Sinopharm) in Healthcare Workers: A Cohort Study.

Insufficient data have been reported about the effect of the inactivated SARS-CoV-2 vaccine (BBIBP-CorV) on the humoral response through time in healthcare workers (HCW). This retrospective cohort studied the information of 252 HCW from a private laboratory, comparing the antibody-mediated response provoked by BBIBP-CorV between HCW previously infected with SARS-CoV-2 (PI) and not previously infected (NPI), employing the Elecsys® anti-SARS-CoV-2 S and the cPass™ SARS-CoV-2 Neutralization Antibody Detection kit at intervals of 21, 90, and 180 days after vaccination. The presence of neutralizing antibodies in HCW 21 days after full vaccination was 100% in PI and 91.60% in NPI. We observed a progressive decrease in antibody levels over time in both groups. Comparing HCW PI with NPI, PI had a 10.9, 14.3, and 8.6-fold higher antibody titer with the Elecsys® anti-SARS-CoV-2 S at 21 (p < 0.001), 90 (p< 0.001) and 180 days (p < 0.001) respectively, compared to NPI. Using the percent of signal inhibition (PSI) of the antibody neutralization cPass™, HCW PI showed a level of 1.3, 2.0, and 3.1 times more antibodies, at 21 (p < 0.001), 90 (p < 0.001), and 180 days (p < 0.001) respectively, compared to NPI. We determined a progressive decrease in humoral immunity over time, particularly higher in those NPI.

Seropositivity of Anti-SARS CoV2 IgG antibodies in health care workers of an Indian tertiary care hospital during COVID-19

PurposeHealth care workers [HCW] are at a higher risk of infection SARS CoV2 infection due to frequent and close contact to patients with COVID-19. MethodsSerum samples from 500 HCW's were tested for SARS CoV2 IgG antibodies in October 2020. A questionnaire was used to collect demographic and clinical data. All these HCWs were tested for COVID-19, in 2nd week of September 2020, as a hospital policy. ResultsAnti SARS CoV2 antibodies were detected in 128/ 500 [25.6%] HCWs. A total of 195/ 500 [39%] enrolled cases had already tested positive for Covid-19 at least once in last six months by RT-PCR. Sixty eight percent of HCWs with previous COVID-19 positivity by RT- PCR tested positive for Anti SARS CoV2 antibodies, whereas only 2.76% of asymptomatic HCWs tested positive. Of 121 anti SARS-CoV-2 IgG positive persons, 70 [57.85%] had CT value ​< ​25. Low CT value and asymptomatic cases had a strong reverse statistically significant association with SARS CoV2 IgG antibody positivity. ConclusionsWe report that sero-conversion rate in HCWs is similar to that in general population suggesting that preventive practices used in hospitals are satisfactory. Cases with low viral counts in respiratory sample and asymptomatic cases have lower rate of seroconversion.

SARS-CoV-2 antibody prevalence among healthcare workers: A cross-sectional study at a quaternary healthcare center in Saudi Arabia

BackgroundThe objective of this study was to determine the seroprevalence of SARS-CoV-2 antibodies among Healthcare Workers (HCWs). MethodsWe carried out a cross-sectional study among 3644 HCWs at King Saud Medical City (KSMC) during the last two weeks of December 2020. A Google form survey was used to collect data on demographics, underlying health conditions, job duties, infection control competencies, COVID-19 exposure history, symptoms, and confirmed infections. Findings26.5% demonstrated seropositivity to SARS-CoV-2 antibodies, 10-fold higher than the national seroprevalence (2.36) conducted in May 2020. Seropositivity was significantly higher among non-Saudi HCWs and participants who lived outside the hospital dormitory p < 0.0001 and 0.01, respectively). Seropositivity was significantly higher among HCWs who worked on clinical areas of high exposure level, and those who spent longer duration working with patients with COVID-19; p = 0.002 and 0.005, respectively). ConclusionSARS-CoV-2 infections among HCWs can go unrecognized, which magnifies the importance of complying with universal masking and social distancing directives. Detecting SARS-CoV-2 antibodies in HCWs can help healthcare leaders in considering staff allocations and assignments accordingly.

High SARS-CoV-2 Seroprevalence among Healthcare Workers in Bamako, Mali.

In Mali, a country in West Africa, cumulative confirmed COVID-19 cases and deaths among healthcare workers (HCWs) remain enigmatically low, despite a series of waves, circulation of SARS-CoV-2 variants, the country’s weak healthcare system, and a general lack of adherence to public health mitigation measures. The goal of the study was to determine whether exposure is important by assessing the seroprevalence of anti-SARS-CoV-2 IgG antibodies in HCWs. The study was conducted between November 2020 and June 2021. HCWs in the major hospitals where COVID-19 cases were being cared for in the capital city, Bamako, Mali, were recruited. During the study period, vaccinations were not yet available. The ELISA of the IgG against the spike protein was optimized and quantitatively measured. A total of 240 HCWs were enrolled in the study, of which seropositivity was observed in 147 cases (61.8%). A continuous increase in the seropositivity was observed, over time, during the study period, from 50% at the beginning to 70% at the end of the study. HCWs who provided direct care to COVID-19 patients and were potentially highly exposed did not have the highest seropositivity rate. Vulnerable HCWs with comorbidities such as obesity, diabetes, and asthma had even higher seropositivity rates at 77.8%, 75.0%, and 66.7%, respectively. Overall, HCWs had high SARS-CoV-2 seroprevalence, likely reflecting a “herd” immunity level, which could be protective at some degrees. These data suggest that the low number of cases and deaths among HCWs in Mali is not due to a lack of occupational exposure to the virus but rather related to other factors that need to be investigated.

Neutralising Antibodies in Healthcare Workers after Two Doses of Covishield Vaccine at Three Months and Six Months: A Single-centre Observational Study

Introduction: The emergence of Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) as a pandemic has put the global population at risk for its infection. It has also led to an accelerated effort to develop vaccines that can mitigate progression to severe infections at a minimum. The ambiguity about existence of antibodies in the human serum poses problem in formulating public health policies like suitable interval between doses of vaccines, appropriate time for vaccinating population, post natural infection, necessity of booster doses along with single dose. Aim: To estimate neutralising antibody level following vaccination of Healthcare Workers (HCWs) after three months and six months respectively. Materials and Methods: This was a prospective observational study performed in Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru, Karnataka, India after Institutional Ethics Committee (IEC) approval from January 2021 to February 2022. The study was conducted in 304 HCWs in the institute who had received two doses of Recombinant ChAdOx1 nCoV- 19 Corona Virus Vaccine (Covishield). 41 HCWs who were naturally infected with SARS-CoV-2 either before or after vaccination were also included. These participants were then subjected to IgG neutralising antibody titer estimation at three months and six months, postvaccination. Results: The study included 304 eligible HCWs. Majority of the participants belonged to the age group of 31-40 years (35.9%). Majority of the study participants were females (51%). Of the 304 participants, 263 were uninfected and 41 participants had been infected before and after vaccination. At the six month follow-up, it was observed that all but one HCW had seroconverted with majority of the participants showing more than 60% antibody level. Participants in the age group of 31-40 years showed the highest level and this observation was found to be statistically significant. Conclusion: Neutralising antibody response in HCWs is a key indicator of the efficacy of the vaccination program for Coronavirus Disease-2019 (COVID-19) in India.

Comparison of the Prevalence of SARS-CoV-2 Nucleoprotein Antibodies in Healthcare Workers and an Unselected Adult and Pediatric All-Comer Patient Population in Austria

Comparison of the Prevalence of SARS-CoV-2 Nucleoprotein Antibodies in Healthcare Workers and an Unselected Adult and Pediatric All-Comer Patient Population in Austria

Seroprevalence of SARS-CoV-2 antibodies in healthcare workers at a tertiary care hospital in Riyadh, Saudi Arabia

BackgroundThe SARS-CoV-2 pandemic has led to a strain on medical resources. The development of countermeasures to prevent its spread is evolving. Healthcare workers (HCWs) are at high risk for contracting and transmitting the disease. MethodsSerology testing of volunteer HCWs was performed at King Faisal Specialist Hospital and Research Center in Riyadh (the Center) in order to determine the prevalence of SARS-CoV-2 antibodies, as well as the associated risk factors, in the hope of implementing adequate prevention and control measures. Results1076 subjects participated in this study, of whom 24.3% were seropositive. The majority were nurses (379, 35%) or physicians (245, 22.2%). 392 (36.4%) of the 1076 subjects were caregivers for COVID-19 patients, and 463 (43.0%) reported contact with infected employees. There was a statistically significant association between taking care of COVID-19 patients and being diagnosed with COVID-19 (chi-square test, p = 0.046). There was a significant association between being in contact with infected employees and having a positive IgG result (chi-square test, p < 0.001). ConclusionsA baseline analysis of SARS-CoV-2 seropositivity in HCWs at a large tertiary care hospital in Riyadh was performed as the first part of a prospective study of HCWs. The reported seropositivity was 24.3% — higher than that of other hospitals in Riyadh. IgG testing was very useful in the detection of previous SARS-CoV-2 infection, as it has high negative predictive value.

Seroprevalence of the SARS-CoV-2 antibody in healthcare workers: a multicentre cross-sectional study in 10 Colombian cities

BackgroundHealthcare workers are at increased risk of infection due to occupational exposure to SARS-CoV-2-infected patients. The objective of this study was to determine the seroprevalence of SARS-CoV-2 in healthcare workers...

The path of uncovering a prothrombotic thrombocytopenic syndrome after viral vector‐based COVID‐19 vaccination: Where there is much light, the shadow is deep

The path of uncovering a prothrombotic thrombocytopenic syndrome after viral vector‐based COVID‐19 vaccination: Where there is much light, the shadow is deep

Prevalence of anti–platelet factor 4/polyanionic antibodies after COVID‐19 vaccination with ChAdOx1 nCoV‐19 and CoronaVac in Thais

IntroductionVaccine‐induced thrombotic thrombocytopenia (VITT) has been reported after vaccination with the adenoviral vector coronavirus disease 2019 (COVID‐19) vaccine ChAdOx1 nCoV‐19 in European countries. To date, two cases of VITT have been reported in Thais after COVID‐19 vaccination. We determined the frequency of anti–platelet factor 4 (PF4)/polyanionic antibodies in the Thai population receiving the COVID‐19 vaccines. MethodsWe conducted a cross‐sectional study to evaluate the prevalence of anti‐PF4/polyanionic antibodies in health care workers who received COVID‐19 vaccination with ChAdOx1 nCoV‐19 or CoronaVac within 7 to 35 days. A control population who had not been vaccinated was also included. Anti‐PF4/polyanionic antibodies were detected using ELISA. Functional assay with platelet aggregation was performed for all positive anti‐PF4/polyanionic antibody ELISA tests. ResultsA total of 646 participants were included in the study; 221 received ChAdOx1 nCoV‐19, 232 received CoronaVac, and 193 participants were in the control group. The prevalence of anti‐PF4 antibodies was 2.3% (95% confidence interval [CI], 0.7‐5.2), 1.7% (95% CI, 0.5‐4.4) in the ChAdOx1 nCoV‐19 and CoronaVac groups, respectively. There was no positive test in the control group. None of the PF4/polyanionic positive sera induced platelet aggregation. ConclusionWe found a low prevalence of anti‐PF4 antibodies in Thais after vaccination with ChAdOx1 nCoV‐19 and CoronaVac. None of the antibodies were functional and lacked an association with VITT.

Prevalence of SARS-CoV-2 IgG antibodies in health care workers at a tertiary care academic medical center – An assessment of occupational infection risk

BackgroundThe purpose of this study was to assess the occupational SARS-CoV-2 infection risk among health care workers (HCW) at University of Kentucky HealthCare (UKHC) by evaluating the prevalence of SARS-CoV-2 antibodies.MethodsThis is a prospective cohort study of HCW at UKHC. SARS-CoV-2 IgG antibody seropositivity was measured in a CLIA-certified laboratory utilizing the Abbott Architect SARS-CoV-2 IgG antibody assay. Demographics and work type were self-reported by study participants via an emailed survey.ResultsThe overall antibody positivity rate of HCW was 1.55% (5/322; 95% confidence interval: 0.65%-3.71%) at cohort entry. There were no differences in antibody positivity between those that worked directly with SARS-CoV-2 infected patients and those that did not. The antibody rate of positivity of patients during the same time period was similar, 1.8% (9/499; 95% confidence interval 0.94%-3.45%).ConclusionsAntibody positivity was low and similar between HCW and patients tested during a similar time period. HCW positivity rates did not appear to be impacted by caring for known SARS-CoV-2 infected patients suggesting that appropriate use of personal protective equipment is effective in protecting individuals from transmission.

Seroprevalence of SARS-CoV-2 Binding and Neutralizing Antibodies in Healthcare Workers during the Epidemic Peak in Referral Hospitals and Quarantine Sites: Saudi Arabia.

Healthcare workers (HCWs) are at high risk for SARS-CoV-2 infection compared to the general population. Here, we aimed to evaluate and characterize the SARS-CoV-2 seropositivity rate in randomly collected samples among HCWs from the largest referral hospitals and quarantine sites during the peak of the COVID-19 epidemic in the city of Jeddah, the second largest city in Saudi Arabia, using a cross-sectional analytic study design. Out of 693 participants recruited from 29 June to 10 August 2020, 223 (32.2%, 95% CI: 28.8–35.8) were found to be confirmed seropositive for SARS-CoV-2 antibodies, and among those 197 (88.3%) had never been diagnosed with COVID-19. Seropositivity was not significantly associated with participants reporting COVID-19 compatible symptoms as most seropositive HCW participants 140 (62.8%) were asymptomatic. The large proportion of asymptomatic SARS-CoV-2 cases detected in our study demands periodic testing as a general hospital policy.

Antinociceptive and Discriminative Stimulus Effects of Six Novel Psychoactive Opioid Substances in Male Rats.

Compounds with novel or fentanyl-like structures continue to appear on the illicit drug market and have been responsible for fatalities, yet there are limited preclinical pharmacological data available to evaluate the risk of these compounds to public health. The purpose of the present study was to examine acetyl fentanyl, butyryl fentanyl, 3,4-dichloro-N-[[1-(dimethylamino)cyclohexyl]methyl]benzamide (AH-7921), 1-cyclohexyl-4-(1,2-diphenylethyl)piperazine (MT-45), 4-chloro-N-[1-(2-phenylethyl)-2-piperidinylidene]-benzenesulfonamide (W-15), and 4-chloro-N-[1-[2-(4-nitrophenyl)ethyl]-2-piperidinylidene]-benzenesulfonamide (W-18) for their relative potency to reference opioids and their susceptibility to naltrexone antagonism using the 55oC warm-water, tail-withdrawal assay of antinociception and a morphine drug discrimination assay in male, Sprague-Dawley rats. In the antinociception assay, groups of 8 rats per drug were placed into restraining tubes, their tails were immersed into 40o or 55oC water, and the latency for tail withdrawal was measured with a cutoff time of 15 seconds. In the drug discrimination assay, rats (n = 11) were trained to discriminate between 3.2 mg/kg morphine and saline, subcutaneously, in a two-choice, drug discrimination procedure under a fixed ratio-5 schedule of sucrose pellet delivery. Morphine, fentanyl, and four of the synthetic opioids dose dependently produced antinociception and fully substituted for morphine in the drug discrimination assay with the following rank order of potency: fentanyl > butyryl fentanyl > acetyl fentanyl > AH-7921 > MT45 > morphine. All drugs that produced antinociception or morphine-like discriminative stimulus effects were blocked by naltrexone. W-15 and W-18 did not show antinociceptive or morphine-like discriminative stimulus effects at the doses tested supporting a lack of opioid activity for these two compounds. These findings suggest that butyryl fentanyl, acetyl fentanyl, AH-7941, and MT-45 have abuse liability like other opioid agonists. SIGNIFICANCE STATEMENT: As novel psychoactive substances appear on the illicit drug market, preclinical pharmacological testing is required to assist law enforcement, medical professionals, and legal regulators with decisions about potential public health risks. In this study, four synthetic opioids, acetyl fentanyl, butyryl fentanyl, AH-7921, and MT-45 produced effects similar to fentanyl and morphine and were blocked by naltrexone. These data suggest the four synthetic opioids possess similar abuse liability risks as typical opioid agonists.