In terms of record speed, vaccines are here and more are on the way. Less than a year after the coronavirus began devastating the world, the first photos raise hopes of wiping the Covid-19 pandemic off the face of the earth.
Today’s programs in the United States and the United Kingdom are the forerunners of immunization campaigns designed to reach the entire population of the planet – all 8 billion people in all corners of the globe.
There are reasons for optimism. Vaccines are the best and perhaps the only way to eliminate infectious diseases: smallpox has been eradicated, and polio is one step away, with only two countries where transmission persists. But global vaccination campaigns take time – usually decades – suggesting that even with the latest technology, money and power behind the unprecedented global attempt to eliminate Covid-19, the disease is unlikely to be eradicated any time soon.
“I would be surprised to see an effective eradication of this virus now that it is everywhere in the world,” said Walter Orenstein, associate director of the Emory Vaccine Center in Atlanta and former head of the immunization program at the US Centers for Disease Control and Prevention. . “I would be shocked at how contagious it is.”
Supply and distribution problems have already surfaced in the opening days of the US campaign, and the UK, the first Western country to start immunization, has vaccinated just 138,000 people in its first week. In the meantime, Europe has not yet started vaccinations and will probably not do so until after Christmas.
Concerns are growing about how long it will take to immunize large tracts of land in the world, beyond a group of rich countries that have acquired early supplies. A global program called Covax, which aims to deploy Covid vaccines worldwide, has secured agreements with developers, including Johnson & Johnson and AstraZeneca Plc. But some of these supplies are expected to come from an experimental inoculation from Sanofi and GlaxoSmithKline Plc that has been postponed and may not be ready until the end of next year.
“It’s very, very, very complicated to make sure we get these vaccines produced and distributed fairly globally, both morally and economically,” Mark Suzman, executive director of the Bill Foundation, told reporters. & Melinda Gates. December 9 call.
Suzman highlighted research showing that wide access to vaccines could bring significant economic benefits to all countries and save many lives. Because rich nations are likely to have more than enough doses to vaccinate their entire population, they should consider reallocating supplies to those most in need, he said.
Mass vaccination has been one of the most successful public health interventions in the world and has played an important role in increasing life expectancy in the United States by more than 50% in the last century. About a third of US deaths in 1900 occurred in children under the age of 5, many of them from diseases such as smallpox, measles and whooping cough, which can now be prevented by immunization.
Some new vaccines have also gained rapid and widespread use, such as vaccines that prevent pneumococcal infections that can cause severe illness in children and adults. The introduction of shingles vaccination has helped prevent millions of people from the painful disease in the last two decades.
A veteran of the World Health Organization’s effort to eradicate smallpox, Orenstein would often immunize himself in front of entire villages to allay safety concerns. The agency decided to try to eradicate the disease in 1959, when it still affected many developing countries, but the effort did not begin until 1967, when the WHO and its members employed more funds and staff.
The smallpox effort initially targeted entire populations, but this has proven impractical, said William Schaffner, an infectious disease specialist at Vanderbilt University, who advised the government on vaccination. The return came when the strategy shifted to identifying cases and then vaccinating everyone nearby, sometimes hundreds of households.
This approach to creating a vaccination ring around cases has been possible, however, as smallpox can be a disfiguring disease, making it relatively easy to identify and spread.
“It has this reputation for spreading fast, but it’s spreading pretty slowly,” Schaffner said. “You also need close enough contact for the transmission to take place.”
These features allowed vaccination teams to identify patients exactly when they became infected and to close all transmission opportunities. Even so, it took two decades for the global effort to contain the last outbreak of 1977.
A better comparison with Covid could be poliomyelitis, an intestinal virus that sometimes causes permanent and severe disease. Poliomyelitis is similar to Covid, because only a minority of infected people – about one in 100 – get extremely ill.
This has created one of the anticipated problems in widespread vaccination against Covid: people who do not believe they are vulnerable to the disease may not want to be vaccinated, even if it could benefit others by maintaining free intensive care units in the hospital. and possibly preventing the transmission of the disease.
However, an important difference with polio is that it can cause severe illness in young children, leaving them paralyzed throughout life, Orenstein said. This is different from Covid, which mainly affects the elderly and the chronically ill. That left a section of the audience indifferent.
“We get more than one death per minute – two deaths per minute in a few days,” he said. “It’s very annoying to see other people’s lack of concern.”
However, even with the spectrum of children paralyzed by polio and a vaccine available for about 65 years, the global elimination of this disease has not yet been achieved. Two countries, Afghanistan and Pakistan, continue to spread due to insufficient vaccination rates, according to the Global Polio Eradication Initiative.
To defeat Covid, “we need to persuade people to get the vaccine,” Anthony Fauci, the US government’s chief infectious disease specialist, said in an interview. “If you have an extremely effective vaccine and only 50% of people get it, you will not have the impact needed to bring a pandemic to such a low level that it no longer threatens society. And this is the goal of a vaccine, just like we did with measles, just like we did with polio, just like the world did with smallpox. “
Most standard immunizations provide protection for years to decades. We still don’t know how long the Covid vaccines will last, Fauci pointed out. And it’s unclear whether they prevent transmission along with protection against symptoms, although studies could soon shed light on that.
The logistical and supply chain challenge facing the world today is “more complicated than usual, because for the first time in history we will introduce more vaccines against the same target at the same time,” said Rajeev Venkayya, president of Takeda Pharmaceutical Co. The vaccine business said in an interview.
This means that countries will need databases to track the launch and ensure that people receive their doses at the right time, as well as systems to monitor potential side effects and share information with the public, he said.
At first, the countries intend to give priority to the most vulnerable people, as well as health care workers and other critical employees, which will greatly reduce deaths and suffering, said Venkayya, a former special assistant for biodefense to US President George W. Bush.
“But the transmission will not decrease dramatically at first. It will take time for the vaccine-driven population to reach a sufficient level of immunity before we can begin to slow down transmission. “
Potentially by the middle of next year, countries such as the United Kingdom and the United States will be able to see a “real damping of transmission,” he said. “This timetable will be delayed in many other parts of the world that do not have this type of early access to vaccines.”
Unvaccinated populations always threaten to reintroduce the disease in areas where herd immunity appears to have taken over. Just last year, the annual number of reported measles cases worldwide increased more than sixfold to about 870,000, the most since 1996, as immunization rates were marked.
The world is likely to see the same level of viral persistence in coronavirus, said Klaus Stohr, a former Novartis AG vaccine executive and WHO official who supported pandemic preparedness efforts.
“The prediction is quite clear: the virus will never be eradicated,” he said. “Why? Because there will always be a large proportion of susceptible population in the community.”
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