Model-based cost-effectiveness analysis of oral antivirals against SARS-CoV-2 in Korea

Cost-effectiveness Analysis of Nirmatrelvir/Ritonavir Compared with Molnupiravir in Patients at High Risk for Progression to Severe COVID-19 in Japan

Background: Nirmatrelvir/ritonavir (NMV/r) and molnupiravir are oral antiviral drugs approved for the treatment of early symptomatic patients with mild to moderate COVID-19 at high risk of progression to severe disease in Japan. Objective: This study evaluated, from a Japanese payer perspective, the cost-effectiveness of NMV/r compared with molnupiravir among patients with COVID-19. Methods: This cost-effectiveness model describes the COVID-19 disease history and the impact of antiviral treatment on short-term and long-term outcomes. Nirmatrelvir/ritonavir was compared with molnupiravir, and in the scenario analysis NMV/r was compared with standard of care over a lifetime horizon. Results: When compared with molnupiravir, NMV/r showed higher quality-adjusted life years (QALYs) (15.752 vs 15.739) and higher total cost (¥6 248 014 vs ¥6 245 829 [US 44   136.86 v s 44 121.42]). The incremental cost-effectiveness ratio was ¥164 934 (US 1165.12 ) p e r Q A L Y g a i n e d , w h i c h w a s l o w e r t h a n t h e w i l l i n g n e s s - t o - p a y ( W T P ) t h r e s h o l d i n J a p a n ( ¥ 5   000   000 / Q A L Y [ U S 35 320.71/QALY]). In the scenario analysis, the incremental cost-effectiveness ratio was ¥3 646 821 (US 25   761.66 ) p e r Q A L Y g a i n e d . O n e - w a y s e n s i t i v i t y a n a l y s i s a n d p r o b a b i l i s t i c s e n s i t i v i t y a n a l y s i s s h o w e d t h a t N M V / r w a s c o s t - e f f e c t i v e c o m p a r e d w i t h m o l n u p i r a v i r a n d s t a n d a r d o f c a r e c o n s i s t e n t l y . A l l r e s u l t s o f o n e - w a y s e n s i t i v i t y a n a l y s i s s h o w e d t h a t t h e i n c r e m e n t a l c o s t - e f f e c t i v e n e s s r a t i o s w e r e b e l o w t h e W T P t h r e s h o l d i n J a p a n . T h e r e s u l t o f t h e c o s t - e f f e c t i v e n e s s a c c e p t a b i l i t y c u r v e s h o w e d t h a t t h e p r o b a b i l i t y t h a t t h e i n c r e m e n t a l c o s t - e f f e c t i v e n e s s r a t i o w a s b e l o w t h e W T P o f ¥ 5   000   000 / Q A L Y ( U S 35 320.71/QALY) was 100.00%. Conclusion: Nirmatrelvir/ritonavir is cost-effective compared with molnupiravir and standard of care from a Japanese payer perspective. This study provides evidence for the cost-effectiveness of NMV/r for patients with COVID-19.

Impact of oral early antiviral therapies for mild-moderate COVID-19 in the outpatient's setting during Omicron era: a pharmacoeconomic analysis

BACKGROUND

Molnupiravir (MOL) and nirmatrelvir/ritonavir (NIR) decreased mortality and hospital admissions in high-risk patients with mild to moderate COVID-19. Nevertheless, there is a lack of data about the pharmacoeconomic impact of these antivirals in the Omicron era. We conducted a pharmacoeconomic analysis assessing the medical costs of the use of these antivirals compared to those occurred in people who refused the treatment.

METHODS

The study included the first 50 patients vaccinated against SARS-CoV-2 of each month who experienced mild to moderate COVID-19 and were consecutively treated with oral antivirals at Padua University Hospital between February 1, 2022, and June 30, 2022. In addition, all consecutive patients who met the criteria for antiviral therapy during this period but opted not to receive treatment were included as control group. The two groups were compared in terms of costs associated with emergency department visits and hospitalizations, which were identified as the primary outcomes of the study.

RESULTS

Nine-hundred-sixty-one patients were analysed, mean age was 67.72 ± 15.19 years and 49% were males. The most prevalent comorbidities were cardiovascular disease (57%), obesity (18) and diabetes mellitus (18%). Two-hundred-fifty-one (26%) patients were treated with MOL (group A), 252/961 (26%) were treated with NIR (group B) and 458/961 (48%) refused antiviral therapy (group C). While a generally more favourable outcomes was observed in the early treated group, no statistically significance differences between hospitalization or emergency department visits were found between group A and C and between group B and C. Total direct medical costs were statistically significantly higher both comparing group A (671.42 ± 460€) vs. group C and comparing group B (1008.42 ± 1562€) vs. group C (446.58 ± 4977€). The main cost driver associated with the increased cost was the antiviral therapy. The average hospitalization cost was 19,334.3 ± 27,030€ for group C, 8956.2 ± 7412€ for group B and 10,267.2€ for group A.

CONCLUSIONS

In the context of the Omicron variant during the COVID-19 pandemic, the use of early oral antiviral agents in vaccinated individuals was found to be more expensive compared to avoid treatment, primarily due to the high costs associated with it. To enhance the efficiency in resource allocation, it is essential to pursue policies aimed at reducing drug costs, along with conducting further pharmaco-economic studies.

Cost-effectiveness analysis of COVID-19 booster doses and oral antivirals: Case studies in the Indo-Pacific

BACKGROUND

Decision-makers in middle-income countries need evidence on the cost-effectiveness of COVID-19 booster doses and oral antivirals to appropriately prioritise these healthcare interventions.

METHODS

We used a dynamic transmission model to assess the cost-effectiveness of COVID-19 booster doses and oral antivirals in Fiji, Indonesia, Papua New Guinea, and Timor-Leste. We conducted cost-effectiveness analysis from both healthcare and societal perspectives using data collated from publicly available sources. We developed an interactive R Shiny which allows the user to vary key model assumptions, such as the choice of discounting rate, and view how these assumptions affect model results.

FINDINGS

Booster doses were cost saving and therefore cost-effective in all four middle-income settings from both healthcare and societal perspectives using 3% discounting. Providing oral antivirals was cost-effective from a healthcare perspective if procured at a low generic price (US$25) or middle-income reference price (US$250); however, their cost-effectiveness was strongly influenced by rates of wastage or misuse, and the ongoing costs of care for patients hospitalised with COVID-19. The cost or wastage of rapid antigen tests did not appear strongly influential over the cost-effectiveness of oral antivirals in any of the four study settings.

CONCLUSIONS

Our results support that COVID-19 booster programs are cost-effective in middle-income settings. Oral antivirals demonstrate the potential to be cost-effective if procured at or below a middle-income reference price of US$250 per schedule. Further research should quantify the rates of wastage or misuse of oral COVID-19 antivirals in middle-income settings.

Cost-utility analysis of molnupiravir for high-risk, community-based adults with COVID-19: an economic evaluation of the PANORAMIC trial

BACKGROUND

The cost-effectiveness of molnupiravir, an oral antiviral for early treatment of SARS-CoV-2, has not been established in vaccinated populations.

AIM

To evaluate the cost-effectiveness of molnupiravir relative to usual care alone among mainly vaccinated community-based people at higher risk of severe outcomes from COVID-19 over 6 months.

DESIGN AND SETTING

An economic evaluation of the PANORAMIC trial in the UK.

METHOD

A cost-utility analysis that adopted a UK NHS and personal social services perspective and a 6-month time horizon was performed using PANORAMIC trial data. Cost-effectiveness was expressed in terms of incremental cost per quality-adjusted life year (QALY) gained. Sensitivity and subgroup analyses assessed the impacts of uncertainty and heterogeneity. Threshold analysis explored the price for molnupiravir consistent with likely reimbursement.

RESULTS

In the base-case analysis, molnupiravir had higher mean costs of £449 (95% confidence interval [CI] = 445 to 453) and higher mean QALYs of 0.0055 (95% CI = 0.0044 to 0.0067) than usual care (mean incremental cost per QALY of £81 190). Sensitivity and subgroup analyses showed similar results, except for those aged ≥75 years, with a 55% probability of being cost-effective at a £30 000 per QALY threshold. Molnupiravir would have to be priced around £147 per course to be cost-effective at a £15 000 per QALY threshold.

CONCLUSION

At the current cost of £513 per course, molnupiravir is unlikely to be cost-effective relative to usual care over a 6-month time horizon among mainly vaccinated patients with COVID-19 at increased risk of adverse outcomes, except those aged ≥75 years.

Cost-effectiveness of nirmatrelvir/ritonavir for high-risk adult outpatients with COVID-19 in Japan

INTRODUCTION

This study aimed to evaluate the cost-effectiveness of nirmatrelvir/ritonavir (Nir/Rit) for adult outpatients with COVID-19 from the perspective of a Japanese public healthcare payer.

METHODS

A cost-effectiveness simulation was conducted comparing Nir/Rit for the outpatient treatment of high-risk COVID-19 patients to best supportive care (BSC) without antiviral or antibody drugs. The analytical model was divided into two phases: the treatment phase, lasting 35 days from the start of COVID-19 treatment, and the post-treatment phase. Patients who survived the treatment phase were assumed to follow a general population survival curve. Expected costs and expected quality-adjusted life years (QALYs) for both BSC and Nir/Rit were calculated for ages 40 to 80 to obtain the incremental cost-effectiveness ratio (ICER). The robustness of the results was evaluated through deterministic and probabilistic sensitivity analysis (PSA).

RESULTS

The ICERs for patients aged 40, 50, 60, 70, and 80 were 18,854,276 Japanese Yen (JPY)/QALY, 8,482,034 JPY/QALY, 4,976,612 JPY/QALY, 2,636,096 JPY/QALY, and 1,597,783 JPY/QALY, respectively. In the deterministic sensitivity analysis, both the mortality risk during the treatment phase and the relative mortality risk with Nir/Rit had a high impact on ICER across all ages. In the PSA, when the willingness-to-pay (WTP) threshold was set at 5 million JPY/QALY, the probability of the ICER being below the WTP threshold was 0%, 0.2%, 45.4%, 99.9%, and 100% at ages 40, 50, 60, 70, and 80, respectively.

CONCLUSION

Nir/Rit is cost-effective for older individuals aged 60 and over but not for younger age groups.

Economic Evaluation of Nirmatrelvir/Ritonavir Among Adults Against Hospitalization During the Omicron Dominated Period in Malaysia: A Real-World Evidence Perspective

BACKGROUND AND OBJECTIVES

Nirmatrelvir/ritonavir was administered orally to manage mild to moderate symptoms of COVID-19 in adult patients. The objectives of this study were to (i) evaluate the cost-effectiveness of prescribing nirmatrelvir/ritonavir within 5 days of a COVID-19 illness in order to avert hospitalization within a 30-day period in the Malaysia setting; (ii) determine how variations in pricing and hospitalization rates will affect the cost-effectiveness of nirmatrelvir/ritonavir.

METHODS

The 30-day hospitalization related to COVID-19 was determined using 1 to 1 propensity score-matched real-world data in Malaysia from 14 July 2022 to 14 November 2022. To determine the total per-person costs related to COVID-19, we added the cost of drug (nirmatrelvir/ritonavir or control), clinic visits and inpatient care. Incremental cost-effectiveness ratio (ICER) per hospitalization averted was calculated.

RESULTS

Our cohort included 31,487 patients. The rate of hospitalization within 30 days was found to be 0.35% for the group treated with nirmatrelvir/ritonavir, and 0.52% for the control group. The nirmatrelvir/ritonavir group cost an additional MYR 1,625.72 (USD 358.88) per patient. This treatment also resulted in a reduction of 0.17% risk for hospitalization, which corresponded to an ICER of MYR 946,801.26 (USD 209,006.90) per hospitalization averted.

CONCLUSION

In Malaysia, where vaccination rates were high, nirmatrelvir/ritonavir has been shown to be beneficial in the outpatient treatment of adults with COVID-19 who have risk factors; however, it was only marginally cost effective against hospitalization for healthy adults during the Omicron period.

Lessons Learned from Model-based Economic Evaluations of COVID-19 Drug Treatments Under Pandemic Circumstances: Results from a Systematic Review

BACKGROUND

Following clinical research of potential coronavirus disease 2019 (COVID-19) treatments, numerous decision-analytic models have been developed. Due to pandemic circumstances, clinical evidence was limited and modelling choices were made under great uncertainty. This study aimed to analyse key methodological characteristics of model-based economic evaluations of COVID-19 drug treatments, and specifically focused on modelling choices which pertain to disease severity levels during hospitalisation, model structure, sources of effectiveness and quality of life and long-term sequelae.

METHODS

We conducted a systematic literature review and searched key databases (including MEDLINE, EMBASE, Web of Science, Scopus) for original articles on model-based full economic evaluations of COVID-19 drug treatments. Studies focussing on vaccines, diagnostic techniques and non-pharmaceutical interventions were excluded. The search was last rerun on 22 July 2023. Results were narratively synthesised in tabular form. Several aspects were categorised into rubrics to enable comparison across studies.

RESULTS

Of the 1047 records identified, 27 were included, and 23 studies (85.2%) differentiated patients by disease severity in the hospitalisation phase. Patients were differentiated by type of respiratory support, level of care management, a combination of both or symptoms. A Markov model was applied in 16 studies (59.3%), whether or not preceded by a decision tree or an epidemiological model. Most cost-utility analyses lacked the incorporation of COVID-19-specific health utility values. Of ten studies with a lifetime horizon, seven adjusted general population estimates to account for long-term sequelae (i.e. mortality, quality of life and costs), lasting for 1 year, 5 years, or a patient's lifetime. The most often reported parameter influencing the outcome of the analysis was related to treatment effectiveness.

CONCLUSION

The results illustrate the variety in modelling approaches of COVID-19 drug treatments and address the need for a more standardized approach in model-based economic evaluations of infectious diseases such as COVID-19.

TRIAL REGISTRY

Protocol registered in PROSPERO under CRD42023407646.

Cost-Utility Model of Nirmatrelvir/Ritonavir in Brazil: Analysis of a Vaccinated Population

OBJECTIVES

The aim of this study is to conduct a cost-utility analysis of the use of the antiviral nirmatrelvir/ritonavir, applied to a vaccinated Brazilian population against COVID-19, from the perspective of the Brazilian Public Health System (SUS).

METHODS

A microsimulation model was created with individual-level data and daily cycles, with a 1-year time horizon, to compare the current scenario of standard care with a scenario in which nirmatrelvir/ritonavir is offered to the population. Adults of any age group that received ≥2 doses of the COVID-19 vaccine formed the investigated population. Direct medical costs of the outpatients and inpatients admitted to the ward or intensive care unit were included. The effectiveness of the model was measured in quality-adjusted life-years (QALYs).

RESULTS

In all simulations, the use of nirmatrelvir/ritonavir resulted in incremental costs per patient of US dollar (USD)245.86 and incremental effectiveness of 0.009 QALY, over a year. The incremental cost-utility ratio was USD27 220.70/QALY. The relative risk of the vaccinated population was the factor that affected the outcome most, according to the univariate sensitivity analysis. The probabilistic sensitivity analysis resulted in 100% of the simulations being more costly and effective, but that only 4% of them were below the established cost-effectiveness threshold of USD24 000.00/QALY. In the scenario considering only the population over 60 years old and immunosuppressed (of any age), the incremental cost-utility ratio was USD7589.37/QALY.

CONCLUSIONS

The use of nirmatrelvir/ritonavir in the treatment of COVID-19 in a vaccinated population was cost-effective only for immunosuppressed individuals and people over 60 years of age.

Assessing the cost-effectiveness of annual COVID-19 booster vaccination in South Korea using a transmission dynamic model

Introduction

We evaluated the cost-effectiveness of South Korea's planned annual coronavirus disease 2019 (COVID-19) booster campaign scheduled for October 2023.

Materials and methods

An age-structured mathematical model was used to analyze the public impacts and cost-effectiveness of vaccination across three vaccination strategies: uniform allocation and prioritizing those over 65 or those over 50 years old. We calculated the incremental cost per quality-adjusted life year (QALY) from both healthcare and societal perspectives. The maximum vaccine cost for cost-effectiveness was also identified.

Results

Our analysis highlights the cost-effectiveness of South Korea's annual COVID-19 vaccination program in mitigating health and economic impacts. The most cost-effective strategy is uniform vaccine allocation, offering the lowest incremental cost-effectiveness ratio (ICER) at US$ 25,787/QALY. However, with a relatively high attack rate, the strategy prioritizing individuals over 65 years emerges as more cost-effective, lowering the ICER to US$ 13,785/QALY. Prioritizing those over 50 was less cost-effective. All strategies were cost-saving from a societal perspective, with cost-effectiveness being more sensitive to vaccine price than to its effectiveness.

Discussion

Our results imply a potential strategy shift in current vaccination plan, with uniform vaccine distribution being more cost-effective than prioritizing older adults. Early estimation of viral transmissibility and vaccine effectiveness is crucial in determining the most cost-effective vaccine allocation approach.

Impact of the Use of Oral Antiviral Agents on the Risk of Hospitalization in Community Coronavirus Disease 2019 Patients (COVID-19)

BACKGROUND

We examined the effectiveness of molnupiravir and nirmatrelvir/ritonavir in reducing hospitalization and deaths in a real-world cohort of nonhospitalized patients with coronavirus disease 2019 (COVID-19).

METHODS

This was a territory-wide retrospective cohort study in Hong Kong. Nonhospitalized COVID-19 patients who attended designated outpatient clinics between 16 February and 31 March 2022 were identified. Patients hospitalized on the day of the first clinic appointment or used both oral antivirals were excluded. The primary endpoint was hospitalization. The secondary endpoint was a composite of intensive care unit admission, invasive mechanical ventilation use, and/or death.

RESULTS

Of 93 883 patients, 83 154 (88.6%), 5808 (6.2%), and 4921 (5.2%) were oral antiviral nonusers, molnupiravir users, and nirmatrelvir/ritonavir users, respectively. Compared with nonusers, oral antiviral users were older and had more comorbidities, lower complete vaccination rate, and more hospitalizations in the previous year. Molnupiravir users were older and had more comorbidities, lower complete vaccination rate, and more hospitalizations in the previous year than nirmatrelvir/ritonavir users. At a median follow-up of 30 days, 1931 (2.1%) patients were hospitalized and 225 (0.2%) patients developed the secondary endpoint. After propensity score weighting, nirmatrelvir/ritonavir use (weighted hazard ratio 0.79; 95% confidence interval [CI], 0.65-0.95; P = .011) but not molnupiravir use (weighted hazard ratio 1.17; 95% CI, 0.99-1.39; P = .062) was associated with a reduced risk of hospitalization than nonusers. The use of molnupiravir or nirmatrelvir/ritonavir was not associated with a lower risk of the secondary endpoint as compared with nonusers.

CONCLUSION

Use of nirmatrelvir/ritonavir but not molnupiravir was associated with a reduced risk of hospitalization in real-world nonhospitalized patients with COVID-19.

Treatment Options for Patients With Mild-to-Moderate Coronavirus Disease 2019 in Korea

The coronavirus disease 2019 (COVID-19) continues to threaten public health in Korea although several surges have passed in the past 3 years since 2019. Although patients with mild-to-moderate COVID-19 can usually recover at home, antiviral therapy to prevent disease progression and hospitalization is beneficial for those at high risk of progressing to severe COVID-19. The purpose of this article was to review how antivirals have been rolled out for the treatment of COVID-19 and how domestic and international guidelines for their use have evolved. Several evidence-based treatment guidelines have been developed in Korea, including those derived from domestic studies. Although many different antiviral agents were nominated as promising therapeutics at the onset of the pandemic, most failed to show efficacy in clinical trials. Currently, three types of antiviral agents-nirmatrelvir-ritonavir, molnupiravir, and remdesivir-are available in Korea to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Each antiviral has its advantages and disadvantages. For most individuals, nirmatrelvir/ritonavir is preferred because of its high efficacy and convenience of administration. When serious drug interactions occur or are expected with nirmatrelvir/ritonavir administration, 3 days of remdesivir treatment is shown to be a reasonable alternative. Molnupiravir may be prescribed with caution only if no other therapeutic options are available or acceptable.

Nirmatrelvir plus ritonavir in COVID-19: a profile of its use

Oral nirmatrelvir plus ritonavir (Paxlovid™) is an effective treatment option for coronavirus disease 2019 (COVID-19), the illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Nirmatrelvir inhibits the main protease of SARS-CoV-2, with ritonavir acting as a pharmacokinetic booster. In the phase II/III EPIC-HR trial, nirmatrelvir plus ritonavir reduced the risk of progression to severe COVID-19 in symptomatic, unvaccinated, non-hospitalized adults with mild-to-moderate COVID-19 at high risk for progression to severe disease. The incidence of COVID-19-related hospitalization or death through day 28 was significantly lower with nirmatrelvir plus ritonavir than with placebo. The efficacy of nirmatrelvir plus ritonavir has also been demonstrated in the real-world setting. Nirmatrelvir plus ritonavir is generally well tolerated, with most adverse events being of mild or moderate severity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40267-022-00971-1.

Comparative effectiveness of sotrovimab and molnupiravir for prevention of severe covid-19 outcomes in patients in the community: observational cohort study with the OpenSAFELY platform

OBJECTIVE

To compare the effectiveness of sotrovimab (a neutralising monoclonal antibody) with molnupiravir (an antiviral) in preventing severe outcomes of covid-19 in adult patients infected with SARS-CoV-2 in the community and at high risk of severe outcomes from covid-19.

DESIGN

Observational cohort study with the OpenSAFELY platform.

SETTING

With the approval of NHS England, a real world cohort study was conducted with the OpenSAFELY-TPP platform (a secure, transparent, open source software platform for analysis of NHS electronic health records), and patient level electronic health record data were obtained from 24 million people registered with a general practice in England that uses TPP software. The primary care data were securely linked with data on SARS-CoV-2 infection and treatments, hospital admission, and death, over a period when both drug treatments were frequently prescribed in community settings.

PARTICIPANTS

Adult patients with covid-19 in the community at high risk of severe outcomes from covid-19, treated with sotrovimab or molnupiravir from 16 December 2021.

INTERVENTIONS

Sotrovimab or molnupiravir given in the community by covid-19 medicine delivery units.

MAIN OUTCOME MEASURES

Admission to hospital with covid-19 (ie, with covid-19 as the primary diagnosis) or death from covid-19 (ie, with covid-19 as the underlying or contributing cause of death) within 28 days of the start of treatment.

RESULTS

Between 16 December 2021 and 10 February 2022, 3331 and 2689 patients were treated with sotrovimab and molnupiravir, respectively, with no substantial differences in baseline characteristics. Mean age of all 6020 patients was 52 (standard deviation 16) years; 59% were women, 89% were white, and 88% had received three or more covid-19 vaccinations. Within 28 days of the start of treatment, 87 (1.4%) patients were admitted to hospital or died of infection from SARS-CoV-2 (32 treated with sotrovimab and 55 with molnupiravir). Cox proportional hazards models stratified by area showed that after adjusting for demographic information, high risk cohort categories, vaccination status, calendar time, body mass index, and other comorbidities, treatment with sotrovimab was associated with a substantially lower risk than treatment with molnupiravir (hazard ratio 0.54, 95% confidence interval 0.33 to 0.88, P=0.01). Consistent results were found from propensity score weighted Cox models (0.50, 0.31 to 0.81, P=0.005) and when restricted to people who were fully vaccinated (0.53, 0.31 to 0.90, P=0.02). No substantial effect modifications by other characteristics were detected (all P values for interaction >0.10). The findings were similar in an exploratory analysis of patients treated between 16 February and 1 May 2022 when omicron BA.2 was the predominant variant in England.

CONCLUSIONS

In routine care of adult patients in England with covid-19 in the community, at high risk of severe outcomes from covid-19, those who received sotrovimab were at lower risk of severe outcomes of covid-19 than those treated with molnupiravir.

Medications for early treatment of COVID-19 in Australia

Early treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections can prevent hospitalisation and death in patients with coronavirus disease 2019 (COVID-19) who have one or more risk factors for serious COVID-19 progression. While early treatment presents a range of logistical challenges, clinicians are nevertheless aided by a growing number of approved medications for early treatment of COVID-19. Medications include drugs that inhibit SARS-CoV-2 viral replication, anti-SARS-CoV-2 monoclonal antibody formulations that provide passive immunisation, and immunomodulatory drugs that suppress the body's inflammatory response. Several drugs with different modes of action are approved in Australia for early treatment of COVID-19, including nirmatrelvir plus ritonavir, molnupiravir, and monoclonal antibody formulations. Although these drugs are recommended, clinicians are encouraged to remain up to date on current indications, contraindications and the clinical efficacy of these drugs against SARS-CoV-2 variants currently circulating in communities. Other treatments, including hydroxychloroquine, ivermectin and dietary supplements, have been popularised but are not recommended for early treatment of COVID-19. As new drugs and new data on use of existing approved drugs become available, clinicians face a growing challenge in determining the optimal treatments from the array of options. As it stands, early treatment of COVID-19 needs to be individualised depending on age, pregnancy status, existing medications, and renal and liver disease status. Future treatments in development might have roles in patients with lower risk profiles and in reducing transmission as we learn to live with SARS-CoV-2.

The Possible Impact of Nationwide Vaccination on Outcomes of the COVID-19 Epidemic in North Korea: A Modelling Study

BACKGROUND

The Democratic People's Republic of Korea (North Korea) had successfully suppressed the coronavirus disease 2019 (COVID-19) epidemic via border closures. However, a rapid surge in incidence was reported due to the spread of the omicron variant (B.1.1.529), leading to a national emergency declaration in May 2022. Moreover, with the lack of vaccine accessibility and medical facilities, it is unclear how the disease burden may be exacerbated. Despite the limited epidemiological data, we aimed to project the COVID-19 transmissions in North Korea and quantify the potential impact of nationwide vaccination, comparing epidemiological outcomes via scenario analysis.

METHODS

A discrete-time deterministic compartmental model was used. The parameters were calibrated using empirical data. Numerical simulations incorporated nationwide COVID-19 vaccination into the proposed model with various asymptomatic proportions.

RESULTS

Our model suggested that the stringent public health and social measures (PHSMs) reduced the severe acute respiratory syndrome coronavirus 2 transmissibility by more than 80% in North Korea. Projections that explicitly incorporated vaccination indicated that nationwide vaccination would be necessary to suppress a huge resurgence in both COVID-19 cases and hospitalizations after the stringent PHSMs are eased. Moreover, vaccinating more than 80% of the population with two doses may keep the peak prevalence of hospitalizations below 1,500, averting more than 40,000 hospitalizations across all scenarios.

CONCLUSION

Nationwide vaccination would be essential to suppress the prevalence of COVID-19 hospitalizations in North Korea after the stringent PHSMs are lifted, especially in the case of a small asymptomatic proportion.

Multi-Faceted Analysis of COVID-19 Epidemic in Korea Considering Omicron Variant: Mathematical Modeling-Based Study

BACKGROUND

The most recent variant of concern, omicron (B.1.1.529), has caused numerous cases worldwide including the Republic of Korea due to its fast transmission and reduced vaccine effectiveness.

METHODS

A mathematical model considering age-structure, vaccine, antiviral drugs, and influx of the omicron variant was developed. We estimated transmission rates among age groups using maximum likelihood estimation for the age-structured model. The impact of non-pharmaceutical interventions (NPIs; in community and border), quantified by a parameter μ in the force of infection, and vaccination were examined through a multi-faceted analysis. A theory-based endemic equilibrium study was performed to find the manageable number of cases according to omicron- and healthcare-related factors.

RESULTS

By fitting the model to the available data, the estimated values of μ ranged from 0.31 to 0.73, representing the intensity of NPIs such as social distancing level. If μ < 0.55 and 300,000 booster shots were administered daily from February 3, 2022, the number of severe cases was forecasted to exceed the severe bed capacity. Moreover, the number of daily cases is reduced as the timing of screening measures is delayed. If screening measure was intensified as early as November 24, 2021 and the number of overseas entrant cases was contained to 1 case per 10 days, simulations showed that the daily incidence by February 3, 2022 could have been reduced by 87%. Furthermore, we found that the incidence number in mid-December 2021 exceeded the theory-driven manageable number of daily cases.

CONCLUSION

NPIs, vaccination, and antiviral drugs influence the spread of omicron and number of severe cases in the Republic of Korea. Intensive and early screening measures during the emergence of a new variant is key in controlling the epidemic size. Using the endemic equilibrium of the model, a formula for the manageable daily cases depending on the severity rate and average length of hospital stay was derived so that the number of severe cases does not surpass the severe bed capacity.