After a year and a half since the first doses were given, the covid-19 vaccines must be updated to combat omicron subvariants, such as BA.1. BA. 4 and BA. 5.
They are expected to be available between September and October 2022, as planned by drug and pharmaceutical regulatory agencies such as Moderna and Pfizer, both producers of vaccines already approved and used on a large scale in much of the world.
“It is highly recommended and necessary that we have new vaccines,” considers the pediatrician and infectologist Renato Kfouri, director of the Brazilian Society of Immunizations.
In practice, the process of updating doses is more complicated than was originally thought.
The main obstacle was the rapid and unpredictable appearance over the past year of new variants of Sars-Cov-2, the coronavirus responsible for the current pandemic. For example, when researchers were working on developing a vaccine to combat the alpha and beta variants, the rise of the delta had already become a problem.
The good news is that vaccines that are currently available and that are administered in three or four doses, depending on the age group and health conditions, continue to protect against the most serious forms of covid associated with hospitalization, intubation, and death.
The BBC spoke to experts to understand the setbacks and possible solutions to increase people’s protection against covid-19 in the future.
In December 2020, when the first vaccines were about to be ready, one of the most circulated information had to do with the eventual ease of updating the doses.
“At first it was said that this process would be very fast, that in about 20 days we could have new vaccines ”, recalls the doctor and epidemiologist Denise Garrett, vice president of the Sabin Vaccine Institute, in the United States.
“As time went, We saw that it wasn’t quite like that.”
The process to make the modifications in the original formulation is not that complicated. In mRNA vaccines, such as those from Pfizer and Moderna, or in viral vector vaccines, such as those from AstraZeneca and Janssen, it is enough to modify the sequence of genes that “teach” our own body to produce protein S, a structure in spike-like shape that sits on the surface of the coronavirus and attaches to cell receptors to initiate infection.
It should be remembered that the first generation of vaccines was developed from the “original” virus, detected in Wuhan (China) at the end of 2019.
The spike (protein S) is the part of the virus that has undergone the most genetic mutations as new variants appear.
The process of “Editing” the sequence of genes in the vaccine is simple and can be done in the laboratory in a few days.
But it is precisely in the next stage where the biggest obstacles appear.
“Modified vaccines must go through clinical trials to see if they work, if they cause an immune response and if they are equally safe,” says doctor Sue Ann Costa Clemens, director of the Oxford-Brazil Vaccine Group in the United Kingdom.
“If all these results are satisfactory, we would enter the regulatory phase in which countries analyze the data and decide if the vaccines will be available for use,” adds the specialist, who is also head of the Institute for Global Health at the University of Siena, in Italy.
In the best case, if the process is done quickly, it takes at least a few months to complete. That’s not counting the time it takes to produce and distribute the millions of doses of the product.
The main issue is that the coronavirus works at a completely different speed: Since the appearance of the omicron variant at the end of 2021, in a few months several sub-variants have emerged with even more infections and with the ability to evade the immune response.
In the first half of 2022 alone, the world saw BA.1 (the first omicron sub-variant) be followed by the BA.2 sub-variant and, recently, by the dominant BA.4 and BA.5 sub-variants.
In addition to this lag, the new versions seem to have more ability to escape the immune response resulting from vaccination and previous covid infections. In fact, the number of people who are being reinfected for the second or third time is increasing with each passing day.
But what will come next? What will be the future variant or sub-variant to worry about? Nobody knows the answer.
How do we solve this equation?
We have both a short-term and a long-term problem. In the coming months, regulatory agencies and pharmaceutical companies must discuss how to speed up that testing and approval process to extend immunity of the people most susceptible to the effects of covid-19.
Along these lines, the US Food and Drug Administration (FDA), seems to have taken a first step.
In late June, agency representatives determined that the booster doses to be used in that country starting in the fall (end of September for the northern hemisphere), they will need to have some sort of protection against subvariants of eithermicron, preferably against BA.4 and BA.5.
Even before this announcement, pharmaceutical companies were already working to update their products. For example, Moderna announced that it was testing a vaccine capable of protecting against the “original” coronavirus and also against the BA.1 subvariant.
The latest results released by the company, which have yet to be reviewed by independent researchers, indicate that the new version of the vaccines they fold the production of neutralizing antibodies against BA.1 compared to older doses.
Pfizer is also making progress on an updated BA.1 vaccine, and early data the company has shared also indicates an increased immune response.
The two laboratories say they are working on specific formulations to broaden protection against the BA.4 and BA.5 subvariants. In this case, this is still at an early stage and the previous results may still take a while to see the light.
Regardless of how this process is going to unfold in the coming months, there is a consensus around finding a way to lessen the virus’ lead in this race, so that the doses used in the next vaccination campaigns are closer to the variant that is in circulation at that time.
“What we need is the vaccination against the coronavirus is something similar to what we currently have for the flufor which the health authorities analyze and determine the strains that will probably circulate with greater intensity in each season”, Garrett proposes.
“From there it would be possible produce vaccines without the need for longer clinical trials and with the entire regulatory approval process“, Add.
However, for this scenario to become a reality, it will be necessary for the circulation of the coronavirus to stabilize.
“We are facing an unpredictable scenario, in which we still cannot predict which variant will circulate in the coming months,” analyzes Kfouri.
Looking at the present with a view to the future
Experts understand that the use of bivalent vaccines, that is, that they protect against the “original” virus and also against the omicron variant, as proposed by pharmaceutical companies, can help solve the problem in the short term. But the future of vaccination necessarily goes through more comprehensive solutions.
“We have to change our strategy. It is no use simply adapting vaccines with each new strain that emergessays Clemens, who is also a senior adviser to the Bill & Melinda Gates Foundation.
“We need to develop solutions capable of protecting ourselves not only from Sars-CoV-2, but from the entire family of coronaviruses, which have the potential to cause other pandemics in the future,” adds the researcher.
These projects, which include technologies such as nanoparticle vaccines or solutions applied through the nose, are still at a very early stage and stronger results will not be seen for another year or two.
Garrett speaks of the need to invest massively in this type of research. “Creating vaccines is a very high-risk business. The chances of one that works well and gets approved is around 7% on average,” she calculates.
“As we are talking about something very risky and very expensive, governments have to make a high investment with pharmaceutical companies. Because without an incentive, these companies alone will not take the risk“, He says.
To get an idea, the government of the United States invested $18,000 million dollars in Operation Warp Speedwhich served as the basis for the development of vaccines and treatments against covid-19 and helped in the creation of the Janssen, AstraZeneca and Moderna vaccines.
Until all these ideas are a realityit is important to follow the guidelines of the health authorities and be up to date with vaccination.
After all, as mentioned above, the doses we currently have continue to protect in most cases against the most serious symptoms that can lead to hospitalization, intubation or even death.
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