Covid19Vaxplorer: A Resource for Vaccine Strategy

The COVID-19 pandemic has had a devastating impact globally, with millions of lives lost and economies affected. As of March 2023, over 6.8 million people have died from the virus. During this time, more than 20 Vaccines have been developed to help combat COVID-19, each with different levels of effectiveness. Countries with higher income have been able to vaccinate a significant portion of their population, while many low-income countries have struggled, with only about 28% of their populations receiving at least one dose.

In some low-income countries, vaccination rates are shockingly low. For instance, places like Haiti and Senegal have less than 10% of their populations fully vaccinated. This disparity highlights the ongoing challenges faced by low-income nations in gaining access to vaccines.

COVAX, a global initiative, was created to help distribute vaccines to these countries. However, as many low- and middle-income countries rely on COVAX, they often receive various vaccines with differing levels of efficacy. This situation challenges public health officials, who must decide how to allocate limited vaccine resources effectively. Unfortunately, many of these regions lack the resources to build Models that could help in understanding the best ways to use their vaccines.

Mathematical modeling has been useful during the pandemic. These models have helped public health officials in several areas, like planning for healthcare capacity, enacting social distancing measures, and managing vaccine rollouts. However, most tools and models have focused on high-income countries, leaving low-income regions with fewer resources and options.

#Introducing Covid19Vaxplorer

To address this gap, we created Covid19Vaxplorer, a free and easy-to-use online tool aimed at helping decision-makers in low- and middle-income countries. This tool simulates COVID-19 outbreaks and vaccination campaigns, allowing users to compare various vaccination strategies tailored to their regions.

Covid19Vaxplorer stands out because it provides a framework for evaluating vaccine allocation decisions, taking into account local demographics, healthcare resources, and vaccine availability. It enables users in 183 regions (covering over 97% of the global population) to simulate the effects of different vaccination plans and to visualize Outcomes, such as expected deaths, hospitalizations, and cases.

#Structure of the Covid19Vaxplorer Model

The Covid19Vaxplorer model is built on a straightforward structure. It uses an age-structured mathematical model to represent how COVID-19 spreads and how vaccine distribution affects this spread. The population is divided into five age groups, from children to older adults, reflecting how the disease impacts different age ranges.

People in each age group can be in various health states: some may be unvaccinated, some vaccinated but losing immunity, and others fully vaccinated. The tool simulates their transition between these states as they react to the virus and vaccines.

#Understanding Vaccine Effects and Allocation

Vaccine products can have different effects on individuals. Some vaccines may reduce the likelihood of infection, while others may lessen the severity of symptoms if a vaccinated person does get infected. Furthermore, individuals who have had COVID-19 before may have some immunity, which can interact with their vaccination status.

Covid19Vaxplorer enables users to create detailed vaccination campaigns. When planning these campaigns, users can specify:

• Which age groups to vaccinate first.
• The percentage of vaccine doses to allocate to each group.
• Whether to deliver primary doses or boosters.

Once the vaccination strategy is set, the tool calculates how many individuals will be vaccinated daily and how long the vaccination campaign will take. The model assumes that people without current infections will receive Vaccinations.

#Simulation Duration and Campaigns

The length of the simulation is crucial when planning vaccine distribution. Users can set start and end dates for their campaigns based on their daily vaccination rates. The tool compares multiple vaccine products and scenarios within the simulation period, allowing users to see how different strategies may affect outcomes.

For those who have been vaccinated before, a booster shot will enhance their immunity. The model treats boosters as renewing the person's protection, regardless of the vaccine type they previously received.

#Design and User Experience

Developing Covid19Vaxplorer was guided by user-centered design principles. The primary audience includes health officials who may not have a technical background but still need to make informed decisions. The aim was to create a tool that is accessible online, free of charge, and easy to navigate.

To ensure the tool met users' needs, the design team conducted research on what officials require in terms of functionality. This input was crucial in structuring the interface to help users progress from basic demographics to complex vaccine allocation considerations.

The design is divided into four main sections:

1. Location: Users enter regional specifics, including demographics, past infections, and social distancing measures.

2. Vaccine: This section focuses on vaccine types available and the effectiveness of each product. Users can choose from pre-loaded vaccines or create custom products.

3. Vaccine Planning: Users specify how many doses are available and the strategy for distribution among age groups.

4. Outcome: The results section displays projected outcomes, allowing users to visualize the impacts of various strategies side by side.

#How Users Can Benefit from Covid19Vaxplorer

Covid19Vaxplorer provides health officials with the ability to input specific local data regarding vaccines, transmission rates, and demographics. This capability allows them to simulate different vaccination scenarios and compare the outcomes of various strategies.

#Scenario Examples

To illustrate the tool's value, two hypothetical scenarios are provided: one for Haiti and another for Afghanistan. Each scenario shows how different vaccination strategies can lead to distinct outcomes regarding hospitalizations and deaths.

#Hypothetical Scenario: Haiti

In this case, we assume that around 29.6% of Haiti's population has been previously infected, leading to some immunity. With a COVID-19 wave expected to hit, Haiti is estimated to receive several million doses of vaccines. The goal is to compare two strategies: one prioritizing booster shots and the other emphasizing primary vaccination for those who have not been vaccinated before.

Using Covid19Vaxplorer, officials can simulate these two approaches. For example, a "Boosters first" strategy could lead to a higher number of deaths compared to a "Primary series first" approach. This capability allows officials to adjust plans based on potential outcomes, making it a vital tool for effective decision-making.

#Hypothetical Scenario: Afghanistan

Another example considers Afghanistan, where a large portion of the population has been infected. With many vaccine doses assigned but not fully utilized, officials can again use Covid19Vaxplorer to determine the best strategy for vaccination. By comparing the results from prioritizing boosters versus primary doses, officials gain insights into potential hospitalizations and overall health outcomes.

#The Importance of Covid19Vaxplorer

The pandemic has underscored the need for tools that help guide vaccine distribution decisions based on data. Many low- and middle-income countries face challenges in determining how to allocate limited vaccine resources effectively.

Covid19Vaxplorer fills this gap by providing an easy-to-use, online tool that empowers users to simulate vaccination strategies and make informed choices. As the situation around COVID-19 evolves, so do the questions regarding vaccine allocation. Officials need to know whether to provide booster shots to high-risk groups or to prioritize vaccinations for unvaccinated populations.

While challenges remain, such as vaccine hesitancy and misinformation, Covid19Vaxplorer allows for a systematic approach to planning. It considers logistical factors such as vaccine availability and distribution challenges.

#Limitations of Covid19Vaxplorer

Every model has its shortcomings, and Covid19Vaxplorer is no exception. Although designed to help with vaccine strategy evaluation, it does not account for every possible variant and its effects on immunity. Additionally, the tool simplifies complex health scenarios into manageable models, which may not capture the full picture of the pandemic's impact.

Users should be cautious when interpreting the results, as real-world situations are influenced by a range of social and health factors. The model serves to provide general guidance rather than precise predictions.

#Conclusion

Covid19Vaxplorer is an innovative solution aimed at supporting decision-makers in low- and middle-income countries manage COVID-19 vaccination efforts. By providing a platform for simulating different vaccination strategies, it empowers officials to make better-informed choices that can ultimately lead to improved health outcomes.

As the pandemic continues to evolve, tools like Covid19Vaxplorer will be essential for addressing the challenges of vaccine distribution and ensuring that all populations receive adequate protection against COVID-19. The importance of equitable vaccine access remains clear, and with tools like this, the hope is to reduce disparities and protect lives globally.

With the right resources, strategies, and tools at their disposal, health officials can make a significant positive impact on the course of the pandemic. Covid19Vaxplorer is just one example of how technology can aid in public health decision-making during these unprecedented times.