Project description:BackgroundDespite the advent of safe and effective COVID-19 vaccines, pervasive inequities in global vaccination persist.MethodsWe projected health benefits and donor costs of delivering vaccines for up to 60% of the population in 91 low- and middle-income countries (LMICs). We modeled a highly contagious (Re at model start = 1.7), low-virulence (IFR = 0.32%) "omicron-like" variant and a similarly contagious "severe" variant (IFR = 0.59%) over 360 days, accounting for country-specific age structure and healthcare capacity. Costs included vaccination startup (US$630 million) and per-person procurement and delivery (US$12.46/person vaccinated).ResultsIn the omicron-like scenario, increasing current vaccination coverage to achieve at least 15% in each of the 91 LMICs would prevent 11 million new infections and 120,000 deaths, at a cost of US$0.95 billion, for an incremental cost-effectiveness ratio (ICER) of US$670/year-of-life saved (YLS). Increases in vaccination coverage to 60% would additionally prevent up to 68 million infections and 160,000 deaths, with ICERs < US$8,000/YLS. ICERs were < US$4,000/YLS under the more severe variant scenario and generally robust to assumptions about vaccine effectiveness, uptake, and costs.ConclusionsFunding expanded COVID-19 vaccine delivery in LMICs would save hundreds of thousands of lives, be similarly or more cost-effective than other donor-funded global aid programs, and improve health equity.
Project description:ObjectivesTo examine the disparities between COVID-19 studies conducted in high-income countries (HICs) and low-and middle-income countries (LMICs).MethodsWe used the International Clinical Trials Registry Platform to identify COVID-19-related studies registered from December 31, 2019 to December 31, 2021. The World Bank definition was used to classify countries as high-, upper-middle-, lower-middle-, and low-income. The last three were considered to be LMICs. We examined the disparities in response speed, classification of medicines and vaccines, and registration and results reporting compliance between COVID-19 studies conducted in HICs and LMICs.ResultsWe included 12,396 COVID-19 studies, with 6631 (53.5%) from HICs. HIC-registered studies reached a peak of 1039 in April 2020, whereas LMICs had only 440 studies. Of the 6969 interventional trials, those from HICs showed higher registration compliance (2199, 62.3% vs 1979, 57.6%, P <0.001) and results reporting compliance (hazard ratio 0.39, 95% confidence interval 0.28-0.55, P < 0.001) than LMICs. HICs also conducted significantly more small-molecule drug (956, 57.5% vs 868, 41.2%, P <0.001) and messenger RNA vaccine trials (135, 32.9% vs 19, 4.8%, P <0.001) than LMICs.ConclusionHICs conducted COVID-19 trials with faster response speed and higher registration and publication compliance and produced more innovative pharmaceutical and vaccine products to combat COVID-19 than LMICs.
Project description:Low- and middle-income countries faced significant challenges in accessing COVID-19 vaccines during the early stages of the pandemic. In this study, we utilized an age-structured modeling approach to examine the implications of various vaccination strategies, vaccine prioritization, and vaccine rollout speeds in Thailand, an upper-middle-income country experiencing vaccine shortages during the early stages of the pandemic. The model directly compares the effectiveness of several vaccination strategies, including the heterologous vaccination where CoronaVac (CV) vaccine was administered as the first dose, followed by ChAdOx1 nCoV-19 (AZ) vaccine as the second dose, under varying disease transmission dynamics. We found that the traditional AZ homologous vaccination was more effective than the CV homologous vaccination, regardless of disease transmission dynamics. However, combining CV and AZ vaccines via either parallel homologous or heterologous vaccinations was more effective than relying solely on AZ homologous vaccination. Additionally, prioritizing vaccination for the elderly aged 60 years and above was the most effective way to reduce mortality when community transmission is well-controlled. On the other hand, prioritizing workers aged 20-59 was most effective in lowering COVID-19 cases, irrespective of the transmission dynamics. Lastly, despite the vaccine prioritization strategy, rapid vaccine rollout speeds were crucial in reducing COVID-19 infections and deaths. These findings suggested that in low- and middle-income countries where early access to high-efficacy vaccines might be limited, obtaining any accessible vaccines as early as possible and using them in parallel with other higher-efficacy vaccines might be a better strategy than waiting for and relying solely on higher-efficacy vaccines.
Project description:BackgroundThe COVID-19 pandemic has disrupted vaccination services and raised the risk of a global resurgence of preventable diseases. We assessed the extent of and reasons for missed or delayed vaccinations (hereafter 'missed') in middle- and high-income countries in the early months of the pandemic.MethodsFrom May to June 2020, participants completed an online survey on missed vaccination. Analyses separated missed childhood and adult vaccination in middle-and high-income countries.ResultsRespondents were 28,429 adults from 26 middle- and high-income countries. Overall, 9% of households had missed a vaccine, and 13% were unsure. More households in middle- than high-income countries reported missed childhood vaccination (7.6% vs. 3.0%) and missed adult vaccination (9.6% vs. 3.4%, both p < .05). Correlates of missed childhood vaccination in middle-income countries included COVID-19 risk factors (respiratory and cardiovascular diseases), younger age, male sex, employment, psychological distress, larger household size, and more children. In high-income countries, correlates of missed childhood vaccination also included immunosuppressive conditions, but did not include sex or household size. Fewer correlates were associated with missed adult vaccination other than COVID-19 risk factors and psychological distress. Common reasons for missed vaccinations were worry about getting COVID-19 at the vaccination clinic (15%) or when leaving the house (11%). Other reasons included no healthcare provider recommendation, clinic closure, and wanting to save services for others.InterpretationMissed vaccination was common and more prevalent in middle- than high-income countries. Missed vaccination could be mitigated by emphasizing COVID-19 safety measures in vaccination clinics, ensuring free and accessible immunization, and clear healthcare provider recommendations.
Project description:Widespread acceptance of COVID-19 vaccines is crucial for achieving sufficient immunization coverage to end the global pandemic, yet few studies have investigated COVID-19 vaccination attitudes in lower-income countries, where large-scale vaccination is just beginning. We analyze COVID-19 vaccine acceptance across 15 survey samples covering 10 low- and middle-income countries (LMICs) in Asia, Africa and South America, Russia (an upper-middle-income country) and the United States, including a total of 44,260 individuals. We find considerably higher willingness to take a COVID-19 vaccine in our LMIC samples (mean 80.3%; median 78%; range 30.1 percentage points) compared with the United States (mean 64.6%) and Russia (mean 30.4%). Vaccine acceptance in LMICs is primarily explained by an interest in personal protection against COVID-19, while concern about side effects is the most common reason for hesitancy. Health workers are the most trusted sources of guidance about COVID-19 vaccines. Evidence from this sample of LMICs suggests that prioritizing vaccine distribution to the Global South should yield high returns in advancing global immunization coverage. Vaccination campaigns should focus on translating the high levels of stated acceptance into actual uptake. Messages highlighting vaccine efficacy and safety, delivered by healthcare workers, could be effective for addressing any remaining hesitancy in the analyzed LMICs.
Project description:ObjectivesThis study aimed to explore the relationship between national governance and country response to the COVID-19 pandemic in low- and middle-income countries, to support preparedness for the next pandemic. We conducted a statistical analysis of 116 countries, examining the relationship between speed of initial response and measures of national governance.Study designObservational study, with individual countries as the unit of analysis.MethodsWe used logistic regression to look for associations between quicker initial government response and four national governance indicators: Government Effectiveness, Political Stability and Absence of Violence/Terrorism, Voice and Accountability, and Corruption Perceptions Index.ResultsA quicker initial government response was associated with countries with higher Government Effectiveness (OR 13.92 95% CI 3.69-52.48, p < 0.001) and lower Political Stability and Absence of Violence/Terrorism (OR 0.23, 95% CI 0.09-0.57, p = 0.002). There was no relationship observed between speed of initial government response and Voice and Accountability or Corruption Perceptions Index. Other factors associated with quicker initial response were small population size, experiencing first COVID-19 case after the pandemic declaration, not having previous experience with SARS-CoV1 or MERS and not being an island nation.ConclusionsThis study shows that having higher state policy and implementation capacity, and lower political stability was associated with a quicker initial pandemic response. Limitations of this study include the use of crude national level indicators and broad categorisations of countries into quicker and slower responders. Deeper enquiry into the early decision-making processes taken at the national executive level within individual countries may help clarify the observed associations further.
Project description:The safe, highly effective measles vaccine has been recommended globally since 1974, yet in 2017 there were more than 17 million cases of measles and 83,400 deaths in children under 5 years old, and more than 99% of both occurred in low- and middle-income countries (LMICs)1-4. Globally comparable, annual, local estimates of routine first-dose measles-containing vaccine (MCV1) coverage are critical for understanding geographically precise immunity patterns, progress towards the targets of the Global Vaccine Action Plan (GVAP), and high-risk areas amid disruptions to vaccination programmes caused by coronavirus disease 2019 (COVID-19)5-8. Here we generated annual estimates of routine childhood MCV1 coverage at 5 × 5-km2 pixel and second administrative levels from 2000 to 2019 in 101 LMICs, quantified geographical inequality and assessed vaccination status by geographical remoteness. After widespread MCV1 gains from 2000 to 2010, coverage regressed in more than half of the districts between 2010 and 2019, leaving many LMICs far from the GVAP goal of 80% coverage in all districts by 2019. MCV1 coverage was lower in rural than in urban locations, although a larger proportion of unvaccinated children overall lived in urban locations; strategies to provide essential vaccination services should address both geographical contexts. These results provide a tool for decision-makers to strengthen routine MCV1 immunization programmes and provide equitable disease protection for all children.
Project description:BackgroundThe expansion of childhood vaccination programs in low and middle income countries has been a substantial public health success story. Indicators of the performance of intervention programmes such as coverage levels and numbers covered are typically measured through national statistics or at the scale of large regions due to survey design, administrative convenience or operational limitations. These mask heterogeneities and 'coldspots' of low coverage that may allow diseases to persist, even if overall coverage is high. Hence, to decrease inequities and accelerate progress towards disease elimination goals, fine-scale variation in coverage should be better characterized.MethodsUsing measles as an example, cluster-level Demographic and Health Surveys (DHS) data were used to map vaccination coverage at 1 km spatial resolution in Cambodia, Mozambique and Nigeria for varying age-group categories of children under five years, using Bayesian geostatistical techniques built on a suite of publicly available geospatial covariates and implemented via Markov Chain Monte Carlo (MCMC) methods.ResultsMeasles vaccination coverage was found to be strongly predicted by just 4-5 covariates in geostatistical models, with remoteness consistently selected as a key variable. The output 1 × 1 km maps revealed significant heterogeneities within the three countries that were not captured using province-level summaries. Integration with population data showed that at the time of the surveys, few districts attained the 80% coverage, that is one component of the WHO Global Vaccine Action Plan 2020 targets.ConclusionThe elimination of vaccine-preventable diseases requires a strong evidence base to guide strategies and inform efficient use of limited resources. The approaches outlined here provide a route to moving beyond large area summaries of vaccination coverage that mask epidemiologically-important heterogeneities to detailed maps that capture subnational vulnerabilities. The output datasets are built on open data and methods, and in flexible format that can be aggregated to more operationally-relevant administrative unit levels.
Project description:BackgroundSARS-CoV-2 has infected a large number of pregnant women.ObjectiveTo compare clinical, perinatal outcomes of women with COVID-19 from high-income countries (HICs) and low- to middle-income countries (LMICs).Search strategyOnline databases were searched.Selection criteriaOriginal studies on pregnant women with COVID-19 were included.Data collection and analysisInformation on clinical presentation, co-morbidities, pregnancy outcomes, neonatal outcomes, and SARS-CoV-2 infection in neonates was extracted.Main resultsThe pooled estimate of SARS-CoV-2 positive neonates is 3.7%. Symptomatic presentations are less common in LMICs compared to HICs (odds ratio [OR] 0.38). Diabetes (OR 0.5), hypertension (OR 0.5), and asthma (OR 0.14) are commonly reported from HICs; hypothyroidism (OR 2.2), anemia (OR 3.2), and co-infections (OR 6.0) are commonly reported in LMICs. The overall risk of adverse pregnancy outcomes is higher in LMICs compared to HICs (OR 2.4). Abortion (OR 6.2), stillbirths (OR 2.0), and maternal death (OR 7.8) are more common in LMICs. Preterm births and premature rupture of membranes are comparable in both groups. Neonatal deaths (OR 3.7), pneumonia (OR 7.5), and neonatal SARS-CoV-2 infection (OR 1.8) are commonly reported in LMICs.ConclusionsIn LMICs, pregnant women and neonates are more vulnerable to adverse outcomes due to COVID-19. PROSPERO registration no: CRD42020198743.