Seroprevalence of hospital staff in a province with zero COVID-19 cases.

BACKGROUND: COVID-19 seroprevalence data, particularly in less developed countries with a relatively low incidence, has been scant. We aimed to explore the seroprevalence of hospital staff in the area with zero confirmed COVID-19 case to shed light on the situation of COVID-19 infection in zero or low infection rate countries where mass screening was not readily available. METHODS: A locally developed rapid immunoglobulin M (IgM)/immunoglobulin G (IgG) test kit was used for hospital staff screening of Ranong hospital which is located in a province with zero COVID-19 prevalence in Thailand from 17th April to 17th May 2020. All staff was tested, 100 of which were randomly invited to have a repeating antibody test in one month. (Thai Clinical Trials Registry: TCTR20200426002). RESULTS: Of 844 hospital staff, 82 were tested twice one month apart (response rate for repeating antibody test 82%). Overall, 0.8% of the participants (7 of 844) had positive IgM, none had positive IgG. Female staff had 1.0% positive IgM (95% CI: 0.5-2.1%) while male had 0.5% positive IgM (95% CI: 0.1-2.6%). No participants with a history of travel to the high-risk area or close contact with PCR-confirmed COVID-19 case developed SARS-CoV-2 antibodies. Among 844 staff, 811 had no symptoms and six of them developed IgM seropositive (0.7%) while 33 had minor symptoms and only one of them developed IgM seropositive (3.0%). No association between SARS-CoV-2 IgM status and gender, history of travel to a high-risk area, close contact with PCR-confirmed or suspected COVID-19 case, presence of symptoms within 14 days, or previous PCR status was found. None of the hospital staff developed SARS-CoV-2 IgG. CONCLUSIONS: COVID-19 antibody test could detect a considerable number of hospital staff who could be potential silent spreaders in a province with zero COVID-19 cases. Accurate antibody testing is a valuable screening tool, particularly in asymptomatic healthcare workers. Trial registration: This study was approved by the Institutional Review Board of Chulalongkorn University (IRB No.236/63) and the Institutional Review Board of Ranong Hospital. (Thai Clinical Trials Registry: TCTR20200426002).

Clinical factors predictive of pneumonia caused by pandemic 2009 H1N1 influenza virus.

Pneumonia was the most common cause of death during the 2009 pandemic H1N1 influenza virus infection. Clinical risk factors for pneumonia caused by this virus are limited. We enrolled consecutive patients treated at the H1N1 Clinic in Thungsong Hospital in Nakhon Si Thammarat, Thailand, during June-December 2009 who had positive polymerase chain reaction results for H1N1 virus. Clinical features for patients given a diagnosis with and without pneumonia were studied. There were 441 patients with positive polymerase chain reaction results for H1N1 virus. Of these patients, 51 (11.56%) had pneumonia. Three independent clinical factors for H1N1 pneumonia were myalgia, dyspnea, and an absolute neutrophil count > 7,700 cells/µL. Adjusted odds ratios (95% confidence intervals) for these three variables were 0.413 (0.173-0.988), 2.625 (1.230-5.604), and 4.475 (1.882-10.644), respectively. Clinical features may be a useful tool for predicting risk for pneumonia caused by H1N1 virus.

Influenza surveillance in southern Thailand during 2009-2010.

The aim of this study was to determine the epidemiology of influenza infection among patients with influenza-like illness by real-time RT-PCR in southern Thailand from August 2009 to January 2011. The predominant strain in Thung Song District was influenza A. Sporadic cases of influenza occured year round but the incidence peaked from August to November 2009 and July to November 2010. During August to November 2009, pandemic H1N1 (pH1N1) activity was observed along with a low level of seasonal influenza co-circulation. Subsequently, seasonal influenza (H3) activity increased and became the predominant influenza strain, with co-circulation with pH1N1 and influenza B during the 2010 influenza season. Continual surveillance of influenza activity is useful for public health planning in southern Thailand and plays a major role in future influenza control and prevention measures.

Pandemic (H1N1) 2009 virus infection: persistent viral shedding after Oseltamivir treatment.

OBJECTIVES: To study pandemic (H1N1) 2009 virological outcomes after Oseltamivir treatment in confirmed cases of pandemic (H1N1) 2009 virus infections. A hospital-based cohort study was conducted in south Thailand, between June and September 2009. METHODS: Throat/swab specimens were tested by real-time reverse transcriptase polymerase chain reaction (rRT-PCR) for pandemic (H1N1) 2009. All 357 confirmed cases (122 inpatients, 235 outpatients), whose received a 5-day Oseltamivir treatment. Post-treatment virological follow-up was performed in 91 eligible cases. The NA gene was screened for the H275Y mutation responsible for Oseltamivir resistance. RESULTS: Thirty-three of 91 patients (36%) had underlying diseases. The duration from the onset of illness to the detection of virus ranged 1-14 days (median 3 days). The rRT-PCR was positive on day 5 of treatment in 24 of 91 patients (26%). Patients with underlying diseases had a higher proportion of post-treatment positive test than those without underlying diseases (15/33 vs 9/58). The rRT-PCR-confirmed viruses detected in all 125 throat swab specimens did not show evidence suggesting Oseltamivir resistance. CONCLUSIONS: Prolonged presence of pandemic (H1N1) 2009 detected by rRT-PCR was found. An extended course of antiviral treatment should be considered in patients with underlying diseases and severe clinical symptoms.