We hope that new and effective vaccines against the coronavirus will soon bring us back to normal life, life before the coronavirus. However, many scientists warn that the emergence of vaccines does not necessarily mean that we will be able to say goodbye to masks in the near future. Scroll down ↓ to find out how vaccines work and why they need to be available to large numbers of people to end social isolation.
Vaccines are considered one of the greatest achievements of modern medicine. According to the World Health Organization (WHO), they prevent two to three million deaths annually from more than 20 life-threatening diseases. Childhood diseases that were common a generation ago are becoming increasingly rare. And smallpox, which killed hundreds of millions of people, has been completely eradicated.
But it took decades to achieve these successes, and we now expect effective vaccines against coronaviruses to deliver similar results in much shorter timeframes. The news that some of the emerging vaccines are more than 90% effective (meaning that about nine out of ten people vaccinated will be protected from Covid-19) has led many to believe that we can soon abandon social distancing and stop using masks. In the U.S. and the U.K., where regulators quickly approved vaccinations and are planning mass vaccination programs, some believe life could return to normal by spring 2021. But many scientists and health experts warn that vaccines are unlikely to restore our normal way of life anytime soon: their initial supplies are very limited, and they are primarily intended for vulnerable populations and health workers on the front lines of the fight against coronaviruses. This was also mentioned by the head of the WHO, Tedros Adhanom Ghebreyesus. “The vaccine will complement our existing tools, not replace them,” he said. “The vaccine itself will not end the pandemic.” “Initial supplies of the #COVID19 vaccine will be limited, so priority will be given to healthcare workers, the elderly and other at-risk groups. We hope this will reduce the number of deaths and enable health systems to cope, but the virus still has room to maneuver”. “The vaccine alone will not stop the #COVID19 pandemic. We will still need to continue:”
This difference in expectations – the optimism of some politicians and the public on the one hand, and the hesitation of many scientists on the other – is partly explained by a misunderstanding of the scale of the problem: how to produce enough vaccine for a sufficient number of people. Not everyone understands that in the case of infectious diseases (transmitted from person to person), vaccinations must be given to a very large number of people in order to provide real protection. The power of a vaccine lies in its ability to protect not only individual patients, but also those around them.
How does the vaccine work? For example, here is Sean. The problem for Shona, and for all of us, is that no vaccine is 100% effective. The measles vaccine is one of the best, protecting 95% to 98% of people. More recently, the Covid-19 vaccines developed by Pfizer/BioNTech and Moderna have not yet achieved 100% efficacy. And we do not yet know if this percentage will decrease over time and to what extent the results will differ from those obtained in clinical trials. This means that about one in ten people will not be protected against Covid-19, even if we vaccinate everyone. Without 100% coverage, which is unlikely in any vaccination program, the number of people at risk will be quite high. They may also be among the most vulnerable: we already know that older people tend to have a weaker response to vaccination, although vaccines against coronaviruses have shown promising results in this regard. In addition, some people may not be able to be vaccinated due to their medical condition, such as those undergoing cancer treatment. This means that a significant number of people around us are still at risk of becoming infected. This could include your friends and family. However, there is a way to indirectly protect everyone: mass vaccination. If we vaccinate enough people, an amazing thing will happen: we will create multiple invisible shields that will break the chain of virus transmission and indirectly protect our vulnerable friends and loved ones. This is sometimes referred to as herd immunity. Here’s how it works.
How vaccinating large numbers of people protects the vulnerable. We explain quickly, simply, and clearly what happened, why it matters, and what will happen next. The number of offers should remain: episodes. End of story. Podcast Advertising. We still do not know (and this is critical to achieving herd immunity) the extent to which current Covid-19 vaccines are capable of preventing transmission or generating immunity that sterilizes the virus, i.e., deprives it of the ability to replicate. We may have to wait to find out for sure, but as one of the developers of the Pfizer/BioNTech vaccine suggests, there is a chance that at least one of the vaccines may help reduce the risk. But even if we assume that vaccines are effective in stopping the spread of the virus, the number of people who need to be vaccinated to fully protect those at risk is very high. This is because even with a significant level of vaccination with an effective vaccine, many people will still be unprotected, says Professor David Salisbury, former director of immunization at the UK Department of Health and a researcher at the UK’s Chatham House think tank. He explains that it all comes down to simple math.
Why do people remain unprotected – even with a significant level of vaccination? Therefore, scientists point out that until we have enough vaccine to inoculate not only those at risk, but also a large part of the population, there will be no end to social distancing. “Simply protecting vulnerable groups in society may prevent deaths among them and reduce the burden on hospitals, but it will not stop the spread of the virus,” says Professor Salisbury. According to him, unvaccinated individuals will continue to spread the virus, infecting both unvaccinated people and those who have been vaccinated but have not developed a protective immune response. This inevitably means that high levels of vaccination must be achieved in people of all ages to prevent the spread of the virus and protect those at risk. Given how interconnected the modern world is in terms of the movement of people and goods, this needs to be done globally. “This is a global pandemic, not a national epidemic, so the virus must be stopped everywhere. Until that happens, no place in the world will be safe,” says Professor Salisbury.
Currently, the global vaccination plan calls for a limited number of doses to be given initially to health care workers and those most at risk from the virus. But some countries, including the United States and the United Kingdom, have already said they plan to vaccinate beyond at-risk groups as soon as supplies allow. The head of the UK’s National Health Service (NHS) has said it may take until April for all the most vulnerable groups to be vaccinated, but the government’s ultimate goal is to vaccinate as many people over the age of 16 as possible. In general, according to WHO estimates, about 65% to 70% of people should have immunity before the spread of the virus stops, you can talk about “herd immunity” and consider the world safe. Professor Azra Ghani, an epidemiologist at Imperial College London, specializes in mathematical modeling of infectious diseases. According to her, to be considered “safe,” 70% of the population needs to be vaccinated. The expert believes that this will eventually return our lives to normal, but achieving this will not be easy, even if there are no unforeseen obstacles. “The vaccine will end the pandemic, the question is when, and that is the most difficult thing to predict because the production of this vaccine is the biggest problem,” says Professor Gani. Immunizing the majority of the UK’s 68 million people is a colossal task, let alone covering the majority of the planet’s 7.8 billion people. Nothing like this has ever been done before. Vaccines and vaccination equipment, such as vials for storing drugs, must be produced in large quantities. Supply will not meet demand for some time. Then the vaccines must be transported from the factories and delivered to medical centers, including remote and hard-to-reach areas around the world. Some vaccines may also require special storage conditions – for example, the Pfizer vaccine must be stored at -70°C.
The United Kingdom is the first country in the world to approve Pfizer’s vaccine. The country’s National Health Service is already setting up a network of mass vaccination centers. But it will be more difficult in other countries. German logistics giant Deutsche Post DHL has already warned that in large parts of Africa, Asia and South America there is a shortage of refrigerators in the final stages of delivery, as well as a lack of storage facilities, which is “the biggest problem” for distributing a significant amount of vaccine. There is another factor that can slow down mass vaccination. Health officials will have to overcome a wave of “vaccine hesitancy” – a growing number of people who do not want to be vaccinated. The WHO considers the “anti-vaccine movement” to be one of the top 10 threats to global health. In the UK, about 36% of people in the British Academy and Royal Society report said they were either not sure or unlikely to agree to vaccination. Similar figures were reported in a YouGov survey in November. This indecisiveness about vaccination, along with the growing flow of misinformation about vaccination – the so-called anti-vaccine movement – may hinder the development of collective immunity in many countries. Professor Gani suggests that there is a need to reassure people who usually get vaccinated but are currently “a bit nervous” because of the speed with which Covid-19 vaccines have been developed. She believes this will be crucial to the mass introduction of the vaccine in the UK. According to her, gaining the trust of the population and getting people to vaccinate means gradually, though not quickly, approaching the level of “herd immunity. Despite the scientific and practical challenges of delivering an effective vaccine in the UK and globally, there is some good news: it appears that first-generation vaccines are largely effective in controlling Covid-19. In the short term, they will help prevent the development of severe illness and death among the most vulnerable people, especially the elderly with pre-existing conditions, as well as healthcare workers who work with coronavirus patients. Pfizer/BioNTech’s claim that their vaccine protects 94% of adults over the age of 65 is an important incentive for this work. The bad news is that it may take months or even years to vaccinate enough people to make the whole world safe and get us back to normal. According to Professor Solsbury, the assumption that vaccines will return us to our usual way of life by Easter next year has given people unrealistic expectations. Unless the spread of the virus is halted, such an outcome is “unlikely,” he said. Even for countries with a strong health infrastructure and experience in mass vaccination programs, breaking the chain of virus transmission will be a challenge, he said. Professor Salisbury believes that while the outlook for high-risk groups will “undoubtedly improve” next year, others will likely need to take additional steps to protect themselves from the virus. He calls this “vaccine plus”.
Professor Gani agrees and believes it will take another two years for “peace to return to normal,” but this process will likely be faster in high-income countries such as the United Kingdom. “But she warns that while vaccines will eventually end the pandemic, they will not rid us of the virus, and the world must continue to vaccinate, as it does for other infectious diseases.” This new era of “vaccine plus” in the fight against Covid-19 seems to be already upon us, and 2021 will likely require us to continue this fight for several months – and perhaps much longer.
The following team worked on this project Text: Lucy Rogers, Animation and Illustration: Sandra Rodriguez Chilleda, additional art: Irene de la Torre Arenas, Development: Evisa Terciu.