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SINGAPORE: Last week, Pfizer announced the first results of its COVID-19 mRNA vaccine, which suggested it could reduce the risk of COVID-19 by 90 percent.
This was followed earlier this week by a similar announcement from the US-based Moderna about its own vaccine, also based on mRNA technology.
Effective COVID-19 vaccines are key to our ability to control the pandemic and resume travel and economic activities without the need for repeat shutdowns.
Therefore, news that it is possible to develop highly effective vaccines against COVID-19 is very welcome, as it has not historically been the case for other respiratory viral infections, such as influenza.
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The final results of the trials are expected in the coming weeks and have yet to be reviewed by the wider scientific community. However, beyond these promising initial results, there are scientific and practical reasons to be cautiously optimistic about the implications for ending the pandemic.
HOW WILL THE VACCINES WORK?
The scientific questions are well recognized and will take time to unravel. We currently do not know how well the vaccine works in specific groups of people.
This is important, because we know that older people and people with underlying medical conditions are at higher risk for serious diseases, but vaccines generally work worse in these groups.
We also need to better understand how these and other COVID-19 vaccines that are being developed actually work from an epidemiological perspective.
For example, if a vaccine prevents infected people from developing COVID-19 symptoms, but doesn’t actually prevent them from becoming infected in the first place, this means that vaccinated people could still pass the infection on to others.
FILE PHOTO: In this illustration taken on October 31, 2020, vials with a label that reads “COVID-19 / Coronavirus Vaccine / Injection Only” and a medical syringe are seen in front of the Pfizer logo. REUTERS / Dado Ruvic / Illustration / Archive Photo
If this is the case, the vaccine will help prevent serious diseases and reduce the strain on health systems, but it will not be enough on its own to eliminate the virus from the population.
Finally, we need to know how long these vaccines protect for and make sure they don’t cause serious and unacceptable long-term side effects. This will require careful studies in vaccinated populations over several months and years.
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What we learn from these studies will be crucial in informing vaccination strategies for years to come to maximize the benefit of these vaccines.
For example, it will tell us if a single vaccination cycle is sufficient to provide long-term protection, or if repeat vaccinations are needed at regular intervals.
It will also provide us with valuable information on what fraction of the population needs to be vaccinated to reach the crucial threshold of herd immunity, the point at which enough people are protected to control epidemics and prevent future resurgences.
CHALLENGES ON A MASSIVE SCALE
However, in the short and medium term, the priority should be to deploy these vaccines as soon as possible in the places where they are most needed. The uncertainty about these scientific issues should not prevent us from moving forward with plans to introduce vaccines that are considered safe and effective in clinical trials.
The faster we present these vaccines, the more we will learn about the best way to use them.
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Introducing these vaccines on a large scale is in itself a formidable challenge. The Pfizer vaccine is in the most advanced stage and around 300 million doses are expected to be available for use next year. This is still a long way from what is needed to control the pandemic globally.
To be effective, Pfizer vaccine must also be stored at -70 degrees Celsius, much cooler than commonly used vaccines.
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Therefore, the distribution of the vaccine requires the construction of infrastructure to maintain the cold chain, which will be particularly difficult in remote areas with unreliable electricity supplies.
MULTIPLE VACCINES BRING OTHER PROBLEMS
Fortunately, there are other promising vaccines in the pipeline based on alternative approaches that may pose fewer logistical challenges. The Moderna vaccine, for example, is based on similar mRNA technology, but has been formulated in a way that allows it to be stored in a standard freezer.
The news that Moderna’s vaccine was almost 95% effective comes a week after Pfizer and BioNTech said their candidate was 90% effective AFP / JOEL SAGET
Having multiple vaccines available increases our chances of protecting a large enough fraction of the population to control the pandemic. But getting these vaccines to people on the massive scale necessary to do so is difficult.
Most countries do not have registries to record vaccines in adults, as they do in children. Such records are important for tracking how many people in the population have been vaccinated and how many doses they have received.
They can also provide important information for monitoring changes in vaccine effectiveness over time.
If multiple COVID-19 vaccines are introduced, these records become even more important in monitoring the performance of each vaccine. Therefore, countries must invest in the infrastructure to develop and maintain these registries, which comes at an additional cost.
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Initially, vaccine supplies will be limited and countries will have to make difficult decisions about who to prioritize for vaccination.
If there are not enough doses of vaccine for everyone, should we prioritize people at the highest risk of serious disease, or health personnel and other essential workers who are at higher risk of becoming infected and infecting vulnerable patients, or those who most contribute to economic and social recovery?
And how do we use vaccination in combination with other control measures? If individuals are vaccinated, should they immediately face less stringent control and movement restrictions?
GUARANTEE EQUALITY AND JUSTICE
From an ethical point of view, it may be reasonable to ease restrictions on those who are at lower risk. But if vaccine supplies are limited and some groups are prioritized, it may mean that these groups also preferentially benefit from greater freedom to travel or engage in activities that provide social and economic benefits.
Public perception of such policies must be carefully considered to avoid backlash, and countries may need to implement measures to reduce the impact on those who cannot initially benefit from vaccination.
A laboratory technician sorts blood samples within a laboratory for a Covid-19 vaccine study at the Research Centers of America (RCA) in Hollywood, Florida AFP / CHANDAN KHANNA
As members of a global community, we should also be concerned about ensuring that these vaccines are allocated fairly so that all countries can share the benefits equitably and not just those who can afford the most.
To this end, the World Health Organization, together with The Vaccine Alliance (Gavi) and the Coalition for Epidemic Preparedness Innovations (CEPI), has spearheaded the global COVAX initiative, with the support of many countries, including Singapore, to ensure that a fraction of vaccine stocks are made available to low-income countries at affordable prices.
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But what does a fair system for global vaccine allocation look like? Should we prioritize the countries most affected by COVID-19-related deaths and related control measures? Or countries where socio-economic recovery will be more difficult without access to vaccines? And how should we measure these criteria? These are questions with no easy answers.
MANAGEMENT OF EXPECTATIONS AND COMMUNICATION OF FOUNDATIONS
Finally, it will be essential to effectively communicate the rationale for vaccination policies to the public.
If vaccine supplies are limited, some population groups will have to wait longer to access vaccines.
It may also be necessary to use different types of vaccines in different groups of people. For example, some vaccines may provide better protection than others for people at high risk for serious disease, such as the elderly.
In addition, some countries may consider making vaccination mandatory for certain groups, such as health workers or those who care for vulnerable people.
A volunteer undergoes tests before receiving the Moderna vaccine in Detroit, Michigan AFP / –
The public should understand why these policies exist and be sure they are not being denied the benefits of vaccination or offered an “inferior” product.
Rumors and misinformation about the safety of COVID-19 vaccines and their impact on the public acceptance of vaccines are already becoming a concern in many countries.
In Singapore, recent surveys indicated that 20 to 30 percent of respondents would not be willing to receive a COVID-19 vaccine even if it was known to be safe and effective.
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Maintaining high confidence in vaccines and countering the spread of misinformation will be key to ensuring that we can achieve sufficient vaccination levels to control the pandemic.
The availability of multiple promising COVID-19 vaccines less than a year into this pandemic is a testament to our ability to address global challenges through science, innovation, and political will.
But we must bear in mind that vaccines are not a magic formula. On the long road to recovery, we are only at the beginning.
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Dr. Clarence Tam is an assistant professor at the National University of Singapore’s Saw Swee Hock School of Public Health. Dr. Voo Teck Chuan is an assistant professor at the NUS Center for Biomedical Ethics at Yong Loo Lin College of Medicine.
