Home isolation and online support strategies to mild COVID-19 epidemic waves in Thailand: preparing for the next (preprint)

Background: Thailand’s fourth and fifth waves of coronavirus disease 19 (COVID-19) started in July and December 2021, respectively, and greatly overloaded the nation’s public health system. The massive imbalance between health resources and patient demand for services was one of the most significant challenges hampering the country’s response to the catastrophic COVID-19 pandemic. Hospital-based facilities were overwhelmed with an exponential rise in new patient numbers, with a rapidly growing backlog of patients with delayed care or even acceptance within the healthcare system. In response, “outpatient self-isolation” (SI), “home-based isolation” (HI), and “community-based isolation” (CI) strategies were adopted to stabilize COVID-19 cases with mild to moderate symptoms. We present the lessons learned from the system management of HI by drawing on the experiences gained at a university hospital that provided patient-to-professional remote support during the pandemic. The vast majority of patients were assigned to HI immediately after being diagnosed with COVID-19. This system enabled remote consultation, needed medications, and survival-kit supplies to be initiated and delivered to patients’ homes. Conclusion: Our investigation indicates that the HI teleconsultation system was a productive approach to COVID-19 management. It allowed a prompt response to patients’ needs and provided timely access to medical support, especially for patients with mild to moderate symptoms.

Immunity response against mild-to-moderate breakthrough COVID-19 (preprint)

BACKGROUND The Omicron variant prevails the Delta variant after December 2021 in Thailand. Both variants of concern embody diverse epidemiological trends and immunogenicity, raising enormous public health concerns. We determined whether biological and clinical characteristics and immunogenicity of patients differ between Delta and Omicron during post-coronavirus disease 2019 (COVID-19) stage. METHODS A retrospective cohort study involved patients with mild-to-moderate COVID-19 who were under a home isolation (HI) strategy. Clinical outcomes and laboratory data of 2704 and 2477 patients during the Delta and Omicron pandemics were analyzed, respectively. We evaluated anti-receptor binding domain immunoglobulin G (anti-RBD IgG) and surrogate viral neutralizing (sVNT) activity in a subset of 495 individuals post-COVID-19 infection during the Delta pandemic. RESULTS Eighty-four percent of all patients received antiviral treatment. The peak cycle threshold (Ct) values, which inversely related to viral load, were lower in the Omicron (19 [IQR=17-22]) compared with the Delta (21 [IQR=18- 26]; p<0.001), regardless of vaccination status. Upper respiratory tract symptoms were common signs during the Omicron compared with the Delta pandemic. At least two-dose vaccination reduced the chance of hospital readmissions by 10-30% and death by less than 1%. Furthermore, anti-RBD IgG and sVNT against the Delta variants tended to be higher among the older individuals after post-COVID 19 infections and expressed in the long interval after two-dose vaccination than in other groups. CONCLUSIONS Mild-to-moderate Delta and Omicron breakthrough infection with prior full vaccination is limitedly immunogenic; thereby exerting reduced protection against reinfection and infection from novel variants. However, this may be only sufficient to prevent hospitalization and death, particularly in countries where vaccines are limited. (ClinicalTrials.gov number, NCT05328479.)

Understanding the Potential Impact of Different Drug Properties On SARS-CoV-2 Transmission and Disease Burden: A Modelling Analysis (preprint)

Background The unprecedented public health impact of the COVID-19 pandemic has motivated a rapid search for potential therapeutics, with some key successes. However, the potential impact of different treatments, and consequently research and procurement priorities, have not been clear. Methods and Findings We develop a mathematical model of SARS-CoV-2 transmission, COVID-19 disease and clinical care to explore the potential public-health impact of a range of different potential therapeutics, under a range of different scenarios varying: i) healthcare capacity, ii) epidemic trajectories; and iii) drug efficacy in the absence of supportive care. In each case, the outcome of interest was the number of COVID-19 deaths averted in scenarios with the therapeutic compared to scenarios without. We find the impact of drugs like dexamethasone (which are delivered to the most critically-ill in hospital and whose therapeutic benefit is expected to depend on the availability of supportive care such as oxygen and mechanical ventilation) is likely to be limited in settings where healthcare capacity is lowest or where uncontrolled epidemics result in hospitals being overwhelmed. As such, it may avert 22% of deaths in high-income countries but only 8% in low-income countries (assuming R=1.35). Therapeutics for different patient populations (those not in hospital, early in the course of infection) and types of benefit (reducing disease severity or infectiousness, preventing hospitalisation) could have much greater benefits, particularly in resource-poor settings facing large epidemics. Conclusions There is a global asymmetry in who is likely to benefit from advances in the treatment of COVID-19 to date, which have been focussed on hospitalised-patients and predicated on an assumption of adequate access to supportive care. Therapeutics that can feasibly be delivered to those earlier in the course of infection that reduce the need for healthcare or reduce infectiousness could have significant impact, and research into their efficacy and means of delivery should be a priority.

Understanding the Potential Role of Therapeutics in Preventing Deaths Due to COVID-19: A Modelling Analysis (preprint)

Background: The unprecedented public health impact of the COVID-19 pandemic has motivated a rapid search for potential therapeutics, with some key successes. However, the potential impact of current and proposed treatments, and consequently research and procurement priorities, have not been clear. Methods: First, we used a model of SARS-CoV-2 transmission, COVID-19 disease and clinical care pathways to explore the potential impact of dexamethasone - the main treatment currently for hospitalised COVID-19 patients - under scenarios varying: i) healthcare capacity, ii) epidemic trajectories; and iii) the efficacy of dexamethasone in the absence of supportive care. We then fit the model to the observed epidemic trajectory to-date in 165 countries and analysed the potential future impact of dexamethasone in different countries, regions, and country-income strata. Finally, we constructed hypothetical profiles of novel therapeutics based on current trials, and compared the potential impact of each under different circumstances. In each case, the outcome of interest was the number of COVID-19 deaths averted in scenarios with the therapeutic compared to scenarios without. Findings: We find the potential benefit dexamethasone is severely limited in settings where healthcare capacity is lowest or where uncontrolled epidemics result in hospitals being overwhelmed. As such, it may avert 22% of deaths in high-income countries but only 8% in low-income countries (assuming R=1.35). However, therapeutics for different patient populations (in particular, those not in hospital and early in the course of infection) and types of benefit (in particular, reducing disease severity or infectiousness) could have much greater benefits. Such therapeutics would have particular value in resource-poor settings facing large epidemics, even if the efficacy or achievable coverage of such therapeutics is lower in comparison to other types. Interpretation: People in low-income countries will benefit the least from advances in the treatment of COVID-19 to date, which have focussed on hospitalised-patients with adequate access to supportive care. Therapeutics that can feasibly be delivered to those earlier in the course of infection that reduce the need for healthcare or reduce infectiousness could have much greater impact. Such therapeutics may be feasible and research into their efficacy and means of delivery should be a priority. Funding: None to declare. Declaration of Interest: None to declare.

Epidemiology, Clinical Characteristics, And Treatment Outcomes Of Patients With COVID-19 At Siriraj Hospital – Thailand’s Largest University-Based Super-Tertiary Referral Center (preprint)

Background: The epidemiology and outcomes of COVID-19 patients in Thailand are scarce. Methods: This retrospective cohort study included adult hospitalized patients who were diagnosed with COVID-19 at Siriraj Hospital during February 2020 to April 2020. Results: Of 1,409 patients who underwent reverse transcription polymerase chain reaction (RT-PCR) testing for SARS-CoV-2, 1,029 patients (73%) had risk factors for COVID-19 acquisition of which 107 patients had laboratory-confirmed COVID-19. Among the 104 patients who were treated with antiviral medications, 78 (75%) received 2-drug regimen (lopinavir/ritonavir or darunavir/ritonavir plus chloroquine or hydroxychloroquine), and 26 (25%) received a 3-drug regimen with favipiravir added to the 2-drug regimen. Disease progression was observed in 18 patients (16.8%). All patients with COVID-19 were discharged alive. Conclusions: The prevalence of COVID-19 was 7.5% among patients who underwent RT-PCR testing, and 10% among those having risk factors for COVID-19 acquisition. Combination antiviral therapies for COVID-19 patients were well-tolerated and produced a favorable outcome.