- Jose Carlos Cueto
- BBC News Mundo
Seven months have passed since Britain’s Margaret Keenan received the world’s first covid-19 vaccine and began to fight the pathogen.
Countries such as the United Kingdom, Israel and the United States appear to be close to the vaccination levels needed to assess a return to normal.
These seven months of mass vaccinations were also marked by uneven rhythms between rich and poor countries and the threat of new options emerging.
While most of the approved vaccines are highly effective against severe illness and death, several unknowns have come to light during vaccination campaigns.
Will we need a third dose, and are vaccines really the way out of the pandemic?
The BBC is examining these and other key questions.
Will I need a third dose of vaccine?
The third dose is a controversy triggered by several events over the past few weeks.
Pfizer is preparing to request a third booster dose from US regulators.
The British public health system is considering providing it to the most vulnerable patients.
And Israel has already started giving it to cancer patients, transplant recipients and others whose vaccine protection has declined.
Israel and the UK have seen continuous and significant declines in morbidity, hospitalizations and deaths for several weeks, but a significant spike in infections has recently been reported due to the progression of the more contagious variant of Delta found for the disease. For the first time in India.
Experts are discussing what is likely to be the first experience with a third vaccine, although the World Health Organization (WHO) objects to this and insists that doses be administered to lagging countries as a vaccine priority.
Dr. Andrew Badley of the Mayo Clinic in the US explains that “there is currently insufficient data to justify the use of a booster vaccine for any patient.”
“Vaccines like vaccines from Pfizer, Moderna or Janssen are very effective in protecting against serious illness, hospitalization and death from any option, including Delta,” he told BBC Mundo.
“Infections occur in people on a full immunization schedule, but this is not as high a public health priority as hospitalizations and deaths. Even though there have been reports of people vaccinated with symptomatic infection, the severity does not come, ”adds Wilbur. Chen is from the University of Maryland School of Medicine in the United States.
“Vaccination always protects against the most severe forms of the disease,” Badley agrees.
There may be exceptions in the future.
“It is possible that a more robust vaccine would require a dose specifically designed for this mutation,” Badley explains.
I don’t know if this could happen in the ‘near’ future, “Chen told BBC World.
It should be noted that not everyone responds the same to vaccines.
“Especially those with a weakened immune system, such as organ transplant patients.”
That is why, while it is not yet fully understood, “it would be nice to have regulatory approved booster doses ready to use should we need them,” says William Schaffner, professor of preventive medicine at Vanderbilt Medical University in Tennessee, USA.
In short, it is now difficult to say for sure whether this additional dose will be needed by the general population. Everything will depend on the duration of the immunity offered and the possible variations. This brings us to the next question.
Is the protection afforded by vaccines fading?
“As with supermarket products, we expect a short shelf life for fruit and a long shelf life for canned food. What about vaccines? ” – compares Wilbur Chen.
The fact that seven months have elapsed since vaccination means that there is no strong evidence on how long protection lasts.
The more time passes and the more data we have, the better scientists will be able to estimate when the defenses will begin to weaken.
“Some vaccines that we know about only protect for a short time, like the annual flu shot or typhoid fever, and you need boosters for them. Others last long, such as yellow fever or measles, ”explains Chen.
Another reason why it is difficult to determine how long protection from a vaccine lasts is the type of protection our body uses to neutralize the virus.
“Antibody levels do not always predict protection. Current evidence suggests that B cell memory may be more reliable. As we understand better, we may need a booster dose for immunity, which diminishes over time, ”says Badley.
Experts call for a distinction between booster doses and dose changes.
Booster doses are intended to prolong protection. The latter are aimed at combating new options.
“If a new option eludes the protection of the vaccines we have, that’s a different matter entirely. A new vaccine will be needed to neutralize the new variant, ”explains Schaffner.
In this case, experts argue that modifying a vaccine is “an easier process than creating a vaccine from scratch, and it will be done relatively quickly, over a period of weeks or months.”
In addition, there is already extensive experience in vaccine modification.
“Every year we analyze the variants of influenza that are circulating around the world and which do not always coincide in the same hemisphere or continent. Each country then prepares specific vaccines for these options. Something similar could happen with the coronavirus, ”Dr. Jose Manuel Bautista, professor in the Department of Biochemistry and Molecular Biology at the Complutense University of Madrid, Spain, told BBC Mundo a few months ago.
In any case, to prevent new options from undermining current vaccination efforts, the virus needs to be brought under control and as soon as possible to protect as many people around the world as possible.
This is why WHO has opposed the consideration of booster doses without first reaching high levels of general immunization.
How long does it take to vaccinate the whole world?
In many wealthy countries, such as the United States, Britain, Israel and the members of the European Union, vaccinations affect an average of 50% of the population, which is already close to group immunity.
However, countries with fewer resources progress much more slowly. In Latin America, with the exception of Chile, most countries have between 10% and 40% of their population vaccinated. In Central America, even less.
In Africa, many countries have less than 10% of vaccines available.
In a recent interview with BBC Brazil, John McConnell, editor-in-chief of one of the world’s most prestigious scientific journals, The Lancet, said that at current rates, vaccines will be available to all residents by 2023. planets.
“The global community must help many countries that do not have effective immunization programs. Beyond humanitarian considerations, there must be a vested interest in the global elimination of COVID-19 to prevent new variants from emerging and then spreading, ”says Schaffner.
“We cannot further divide the world by prioritizing booster doses when there is still no scientific evidence to back it up. It will only benefit the rich countries, ”Chen agreed.
Will global vaccination be the end of COVID-19?
From the start of the pandemic, it has been said that herd immunity, the act of fighting a disease or vaccination will help control the pandemic.
Control is not synonymous with eradication. The latter is a possibility that some scientists consider increasingly distant, if not impossible.
We shouldn’t wait for the “final end of the coronavirus.” It’s impossible. Like the flu, Sars Cov-2 is already part of our microbial environment, and we will have to fight it. This virus is part of the “new normal,” notes Schaffner.
This is something that some governments are starting to take into account as well.
Faced with a significant increase in cases after vaccinating more than half the population, the UK decided on July 19 to lift all restrictions.
This initiative has sparked controversy and is considered risky by scientists. However, UK Health Minister Sajid Javid defended the measure, saying “we must learn to live with the virus” and that “there was no perfect time to open up the country.”
Given the near impossibility of completely eradicating the virus, Wilbur Chen offers some hope, albeit on a purely theoretical level.
“If we theoretically vaccinate young people, the elderly, adults and children, we may have a chance to eradicate the virus, but that will not prevent a new virus from emerging,” he explains.
“We have eradicated smallpox with vaccines and have nearly eradicated polio, although we now clearly see infections re-emerging in areas where it was impossible to maintain active vaccination,” he says.
Scientists insist that understanding this virus takes time and an ongoing process. Some unknowns will be removed, new ones will appear. One thing is clear: we already have the best weapons, vaccines.
The motto is to continue vaccination, and to do it faster and faster.