Like traveling to the moon in the 1960s, getting vaccinated against the Covid virus has become a career. It is also an unprecedented scientific and technological challenge to achieve something that has never been done before. And it is a project that affects all humanity. But unlike the trip to the moon, this time it’s not a race between two rival countries vying for technological supremacy and glory. This time it is a global effort involving governments, pharmaceutical companies, and philanthropic organizations. All against the virus.
There are already 120 vaccines in development against the SARS-CoV-2 coronavirus, according to a registry that maintains the London School of Hygiene and Tropical Medicine. Ten of them have already been tried on people. It is an unprecedented feat. Candidate vaccines against a virus have never been obtained before only four months after discovery.
The first phase I clinical trials are conducted with few volunteers and are aimed at analyzing the safety of vaccines. Five of the candidates have already gone on to phase I / II or phase II trials, in which the efficacy of the vaccines is beginning to be analyzed.
Among these more advanced is a vaccine from the Oxford University (United Kingdom) that it has successfully immunized macaques and will be tested in a study of 6,000 participants starting next month. Its development has been accelerated because it is inspired by another vaccine created against the MERS coronavirus that proved to be safe but was never approved.
There are also three vaccines developed by Chinese academic institutions and biotech companies (Sinovac, Canino and the Beijing Institute of Biological Products). And a vaccine in which the German collaborate BioNTech and the American Pfizer which is testing a new RNA-based immunization technology for the first time in people. With this technology, viruses or virus particles are not inoculated, but directly the genetic instructions to produce the antigens that will stimulate the immune system.
A preventive vaccine must stimulate the immune system to prevent disease. “The problem is that we do not know the response of the immune system to this virus; we are all running without knowing how to walk ”, he declares Christian brander, investigator Icrea vaccine specialist at the institute IrsiCaixa in Badalona. “But we are in an emergency situation and we need to develop a vaccine as soon as possible.”
It is still unknown which of the more than one hundred candidates that are developing will stimulate immunity effectively and how long its effect will last. The only way to find out will be through clinical trials in which the vaccine is inoculated into one group of volunteers, a placebo is inoculated into another group and you wait to see the results. These tests are usually carried out in groups at high risk of contracting an infection and it takes months or years to obtain results.
To speed up research, a growing number of researchers are advocating for clinical trials in which healthy young volunteers are exposed to the coronavirus to try to infect them. Comparing how many become ill between those who receive the vaccine and those who receive the placebo, it would be known in a matter of weeks if the vaccine is effective. “These people are at high risk of contracting the infection. By participating in the study, they would have optimal medical control. From a bioethical point of view, it seems like a good option, “says Brander.
Since vaccines are given to people who are usually healthy, they cannot have side effects that are acceptable in drugs for sick people. “They must demonstrate that they are extremely safe. The regulation is very guaranteeing. It is something that makes sense under normal conditions, but it can become an obstacle in an emergency situation like the current one ”, he declares Manel Juan, head of the hospital’s immunology service Clinic in Barcelona.
There are concerns that some vaccines may increase the risk of contracting the same disease that they claim to prevent. This paradoxical effect can be produced by an immunological phenomenon in which some antibodies help viruses to enter cells. The phenomenon, called antibody-dependent potentiation, has been described with the Zika, Dengue, and Yellow Fever viruses. It has been hypothesized that it could also occur with coronaviruses. Vaccines approved against other diseases do not have this problem.
The great bottleneck
To prevent Covid, it is not enough to get an effective and safe vaccine. In addition, you need to have the ability to mass-produce and distribute it worldwide. “This may be the bottleneck that delays the vaccine the most,” says Christian Brander. “There may be a safe and effective vaccine in the coming months but we may not have the capacity to produce it in sufficient quantity.”
Anticipating this problem, the Coalition for Innovations in Epidemic Preparedness (CEPI), the GAVI Vaccination Alliance and the Bill and Melinda Gates Foundation have advocated the need to start mass production of vaccines before ending clinical trials so that, if they are safe and effective, they can be distributed as soon as possible.
All three organizations have contributed to the Accelerator ACT program launched by the World Health Organization (WHO) and the European Commission. The program has raised € 7.4 billion this week to accelerate the development of vaccines, drugs and tests against Covid and ensure that everyone has equal access to them.
“Past experience has taught us that, even when tools are available, they are not available to everyone; We cannot allow this to happen, ”said Tedros Adhanom, WHO Director General, on April 24, referring to the lack of equity in the distribution of influenza vaccines during the 2009 pandemic.
No one knows yet when safe and effective vaccines will be available in sufficient quantities to immunize much of the population against coronavirus. Anthony Fauci, Donald Trump’s chief scientific adviser on the coronavirus, stated in an interview on April 30 that having hundreds of millions of doses of a vaccine in early 2021 “is feasible if things fall into place.”
This calendar does not include the time necessary to approve the marketing of the vaccine, but refers only to the time to obtain it, check its efficacy and safety, and mass produce it. The authorization of a new vaccine usually requires more than a year.
To speed up the distribution of vaccines before their sale is approved, some companies have announced that they will resort to the concept of emergency use. This concept allows the administration of products that have obtained positive results but have not yet completed their development to risk groups such as, in this case, health professionals. This is the case of the Chinese CanSino and the American Johnson and Johnson, which plans to have a vaccine ready for emergency use in early 2021.
All of these forecasts assume that unforeseen scientific obstacles will not appear to delay obtaining the vaccine.