The race to find a vaccine against "Covid-19" continues apace. According to the warnings of the World Health Organization, reaching a vaccine or effective treatments will not lead to eradicating the disease, so what are the reasons that explain this, have infectious diseases been eliminated in the past, and what are the reasons for making similar statements, and then what prevents this virus from disappearing?
Writer Tifenn Clinkemaillié says in a report published in the French newspaper Lesechos.fr, that the emerging corona virus, which has infected about 20 million people, may not die.
"This virus can be added to the list of endemic viruses circulating in our societies, and it may never completely disappear," explains Michael J. Ryan, a specialist in health emergencies at the World Health Organization.
The Director-General of the World Health Organization, Tedros Adhanom Ghebreyesus, confirmed, at the beginning of this August, that "there is no cure for the Corona virus, and there may never be a future."
Can an infectious disease be eliminated?
Francois Reno, a researcher at the National Center for Scientific Research and a specialist in infectious diseases, responded categorically to this question, "It is impossible to completely eliminate infectious diseases, and there is one exception regarding smallpox that the World Health Organization has declared eliminated."
He adds, "Regardless of this exception, and to this day, it is not possible to confirm the disappearance of any infectious disease. This is evidenced by the return of influenza annually and measles has existed for thousands of years," and therefore some diseases never disappear.
"The virus must be contained and coexisted," explains Francois Reno, and currently controlling the emerging corona virus depends on respecting preventive measures and social distancing. In the long term, other means, such as vaccines and treatments, can help contain the epidemic without eliminating it.
"By means of treatments, we can today stop the human immunodeficiency virus (responsible for AIDS), because infected people do not have enough viruses to transmit it," explained Stéphane de Witte, an infectious disease specialist at the University Hospital Center, Saint-Pierre, to French-speaking Belgium Radio and Television.
Why is the vaccine not a panacea?
The strength of this virus lies in its diversity, and Francois Reno explains that "vaccines are constantly evolving, as there is a vaccine annually for influenza, and annually people die because of virus mutations", and it is impossible for scientists to know the forms that future mutations will take.
"If there are many changes to the virus, the vaccine will be less effective," says a specialist in infectious diseases, Francois Reno, adding that "the game of genetic combinations is very effective."
Therefore, it will depend on the ability of health systems to adapt their response over the years. Commenting on attempts to find a vaccine, he said it was an "arms race".
Despite this, the researcher maintains his optimism, saying, "The emerging corona virus is a single-stranded RNA virus, unlike the multi-threaded influenza virus," therefore, mutations of the emerging corona virus may be less diverse than the influenza virus.
The other difficulty is that inventing a vaccine takes time, especially as it will be the first vaccine against the Corona virus. The announcement of the first Russian vaccine has prompted a reaction by specialists.
The World Health Organization said that before any "pre-qualification" on its part, it had to check through "stringent procedures" all data collected during clinical trials conducted in Russia.
Francois Palo, a professor at the Institute of Genetics at University College London, said that the Russian declaration was "discredited and meaningless", because no product has been properly tested and could have serious consequences.
Is herd immunity achievable?
"Today, we know nothing about this issue, or we have scant information about herd immunity in relation to this viral epidemic," Francois Reynault said. Group immunity can occur when the majority of the population naturally develops immune resistance, but this phenomenon is particularly effective when there is a potential vaccination, which acts as a firewall.
According to the researcher at the National Center for Scientific Research, "There is currently no vaccine, and for individuals who have already contracted the disease, we still do not know the true coverage that we have or the extent of their immunity continuity."
Collective immunity in the time of Corona
Several studies, particularly by the Pasteur Institute, provide some answers in this regard. On May 13, the institute estimated that only about 4.4% of the population had been affected by Corona, which is much less than the 60% needed to achieve herd immunity.
With regard to continuity, a British study, not yet evaluated, shows that antibody-based immunity fades within months, a factor that may make developing herd immunity complicated, if not impossible.
According to the study, "If the infection shows antibody levels that decrease within two to three months, the vaccine may do the same, and one dose may not be sufficient."
Post-Covid Syndrome
British expert Paul Garner, an infectious disease specialist in Liverpool, explains that "because former patients who are believed to have been cured complain of a return of symptoms, according to provisional estimates, post-Covid syndrome can affect 5 to 10% of French people with corona."
He confirms that "no one knows to what extent the disease can cause immune changes in the body, or any strange diseases that cannot be explained now."
He added, "We can assume that there will be severe pulmonary, neurological, cardiac and musculoskeletal complications in some Covid-19 survivors, which leads to restriction of activity," according to the expectations of the Supreme Health Authority in a note published on April 16 last year.