Since the beginning of COVID-19 pandemics many countries were facing challenges with testing capacity recourse limitations. Throughout the waves of the pandemic countries were trying to address the existing constrains...Since the beginning of COVID-19 pandemics many countries were facing challenges with testing capacity recourse limitations. Throughout the waves of the pandemic countries were trying to address the existing constrains exploring solutions to increase the testing capacity with more cost-effective approaches. Pooled methodology was one of the methods which many have validated and used. It is evident that in case of pooled sample testing the sensitivity becomes lower, however the variation highly depends on the pool size as well as the incidence rate at the certain point. Armenia as well as many other countries has adopted regulations for mandatory COVID-19 PCR testing for all the travelers. Current study aimed to explore the efficiency of COVID-19 pooled PCR testing for nasopharyngeal swabs of individuals with no symptoms in a time period with good epidemiological state of the infection. Nasopharingeal swab samples from individuals were collected. The manual extraction of RNAs of samples was performed after pooling up to 5 samples. The pools with Cycle Threshold (CT) of < 37 were considered positive and were retested individually. In total 28,015 samples were grouped in 667 pools of which 57 were positive. The total number of positive samples was 65. The median difference (CT-pool–CT samples) was 2.4 (ranging from–3.0 to 8.9). The correlation of CT of pools and positive samples was positive. The correlation coefficient r = 0.84, P < 0.000, 95% CI range 0.7423 to 0.9243). The total economic saving when using pools compared to the individual testing was 72%. The minor difference between CT values of pools and samples can be explained by the dilution effect in the pool. However, the positive correlation between the values as well as the amount of cost saving demonstrate that pooling on nasopharyngeal samples for COVID-19 PCR testing can be a good method for efficient screening with significant resource saving. One of the most important advantages of the proposed method is the fact that samples are pooled prior extraction, which avoids the possibilities with misinterpretation of IC due to low yield of RNA in the extraction process.展开更多
Background: In December 2019 in Wuhan China the new coronavirus outbreak emerged and quickly spread in all parts of the world resulting to more than 500,000,000 infection cases and around 6,200,000 deaths. The global ...Background: In December 2019 in Wuhan China the new coronavirus outbreak emerged and quickly spread in all parts of the world resulting to more than 500,000,000 infection cases and around 6,200,000 deaths. The global incidence of the infection is still growing as well as number of deaths. COVID-19 is a new virus, therefore not much is known about the immune response of infected organism, which is crucial not only for vaccination policy development, but also for identification of public health strategies. Aim: Current research aims to describe COVID-19 IgG levels depending on symptoms, antibiotic and antiviral medications intake history, existing chronic condition and smoking status during March-December of 2020 in Armenia. Furthermore, the study aims to help elucidate the fraction of asymptomatic or presymptomatic/sub- clinical infections in the population and understand the main risk factors for infection complication. Methodology: The cross-sectional study with convenience sampling of individuals who turned to “EcoSense” laboratories to be tested for COVID-19 IgG were examined. The NovaTec SARS-CoC-2 (COVID-19) IgG COVG940 96 Determinations ELISA test kits were used. The questionnaire was filled regarding the COVID-19 status, symptoms, exposure history, disease history, pre-existing chronic conditions, medication and vaccination history. The descriptive as well as multivariate analysis was performed. Results: Overall 1573 testing was performed 837 of subjects agreed to participate in the interview. 24.1% of participants had laboratory confirmed COVID-19 but by the time of interview were already recovered. 212 (25.3%) participants had positive IgG levels, among 126 (15.1%) participants IgG levels were in the grey zone. Out of PCR confirmed cases only 58.7% had positive IgG levels and 3.9% IgG level was in the grey zone. Headache was the most common symptom among participants (37.2% among all participants and 53.1% among participants who previously had positive COVID-19 PCR test). The second most common symptom was anosmia (23.7% among all participants and 48.9% among participants who previously had positive COVID-19 PCR test). 5.4% of participants mentioned previous hospitalization due to COVID-19, 71 (8.5%) mentioned being diagnosed with pneumonia and 24 (2.9%) participants mentioned being admitted to ICU, 20 (2.4%) mentioned receiving oxygen therapy and 4 (0.5%) of the participants mentioned receiving an artificial ventilation of lungs. There was a weak correlation between symptom sum score and IgG titers. The Correlation coefficient was 0.273, p Conclusions: Our study reviled that around half of PCR confirmed COVID-19 patients do not have positive titer for IgG, most importantly the number of symptoms is a weak predictor for IgG levels, which contradicts the existing misassumption regarding severity of clinical manifestation of COVID-19 and post-infection immunity.展开更多
文摘Since the beginning of COVID-19 pandemics many countries were facing challenges with testing capacity recourse limitations. Throughout the waves of the pandemic countries were trying to address the existing constrains exploring solutions to increase the testing capacity with more cost-effective approaches. Pooled methodology was one of the methods which many have validated and used. It is evident that in case of pooled sample testing the sensitivity becomes lower, however the variation highly depends on the pool size as well as the incidence rate at the certain point. Armenia as well as many other countries has adopted regulations for mandatory COVID-19 PCR testing for all the travelers. Current study aimed to explore the efficiency of COVID-19 pooled PCR testing for nasopharyngeal swabs of individuals with no symptoms in a time period with good epidemiological state of the infection. Nasopharingeal swab samples from individuals were collected. The manual extraction of RNAs of samples was performed after pooling up to 5 samples. The pools with Cycle Threshold (CT) of < 37 were considered positive and were retested individually. In total 28,015 samples were grouped in 667 pools of which 57 were positive. The total number of positive samples was 65. The median difference (CT-pool–CT samples) was 2.4 (ranging from–3.0 to 8.9). The correlation of CT of pools and positive samples was positive. The correlation coefficient r = 0.84, P < 0.000, 95% CI range 0.7423 to 0.9243). The total economic saving when using pools compared to the individual testing was 72%. The minor difference between CT values of pools and samples can be explained by the dilution effect in the pool. However, the positive correlation between the values as well as the amount of cost saving demonstrate that pooling on nasopharyngeal samples for COVID-19 PCR testing can be a good method for efficient screening with significant resource saving. One of the most important advantages of the proposed method is the fact that samples are pooled prior extraction, which avoids the possibilities with misinterpretation of IC due to low yield of RNA in the extraction process.
文摘Background: In December 2019 in Wuhan China the new coronavirus outbreak emerged and quickly spread in all parts of the world resulting to more than 500,000,000 infection cases and around 6,200,000 deaths. The global incidence of the infection is still growing as well as number of deaths. COVID-19 is a new virus, therefore not much is known about the immune response of infected organism, which is crucial not only for vaccination policy development, but also for identification of public health strategies. Aim: Current research aims to describe COVID-19 IgG levels depending on symptoms, antibiotic and antiviral medications intake history, existing chronic condition and smoking status during March-December of 2020 in Armenia. Furthermore, the study aims to help elucidate the fraction of asymptomatic or presymptomatic/sub- clinical infections in the population and understand the main risk factors for infection complication. Methodology: The cross-sectional study with convenience sampling of individuals who turned to “EcoSense” laboratories to be tested for COVID-19 IgG were examined. The NovaTec SARS-CoC-2 (COVID-19) IgG COVG940 96 Determinations ELISA test kits were used. The questionnaire was filled regarding the COVID-19 status, symptoms, exposure history, disease history, pre-existing chronic conditions, medication and vaccination history. The descriptive as well as multivariate analysis was performed. Results: Overall 1573 testing was performed 837 of subjects agreed to participate in the interview. 24.1% of participants had laboratory confirmed COVID-19 but by the time of interview were already recovered. 212 (25.3%) participants had positive IgG levels, among 126 (15.1%) participants IgG levels were in the grey zone. Out of PCR confirmed cases only 58.7% had positive IgG levels and 3.9% IgG level was in the grey zone. Headache was the most common symptom among participants (37.2% among all participants and 53.1% among participants who previously had positive COVID-19 PCR test). The second most common symptom was anosmia (23.7% among all participants and 48.9% among participants who previously had positive COVID-19 PCR test). 5.4% of participants mentioned previous hospitalization due to COVID-19, 71 (8.5%) mentioned being diagnosed with pneumonia and 24 (2.9%) participants mentioned being admitted to ICU, 20 (2.4%) mentioned receiving oxygen therapy and 4 (0.5%) of the participants mentioned receiving an artificial ventilation of lungs. There was a weak correlation between symptom sum score and IgG titers. The Correlation coefficient was 0.273, p Conclusions: Our study reviled that around half of PCR confirmed COVID-19 patients do not have positive titer for IgG, most importantly the number of symptoms is a weak predictor for IgG levels, which contradicts the existing misassumption regarding severity of clinical manifestation of COVID-19 and post-infection immunity.
