More than a year and seven months after the Covid-19 virus began, anticipation of a normal return to life is growing worldwide. As vaccination progresses,.
With the arrival of new, more contagious variants increasingly adapted to humans, like deltaHowever, the question arises whether Covid-19 is a disease that can be eradicated or whether we will continue to live with Sars-CoV-2 for many years.
Compared to other infectious diseases that challenged humanity in the past, such as smallpox and polio, it is possible to eradicate Covid-19 more easily than polio, But with a little effort For what is required to eradicate smallpox.
This is what a group of New Zealand scientists argue about condition It was published on Monday (9) in the specialized journal BMJ (British Medical Journal).
To reach this conclusion, the researchers developed a score (score) for the susceptibility of a particular disease, and analyzed 17 variables—starting with technical issues, such as having Effective vaccines against the infectious agent, even socio-economic, such as Public investment in other preventive measures and popular acceptance of both vaccination and other protective barriers.
Each factor receives a score from 0 to 3, with higher scores corresponding to greater ease of eradication. In the classification of the three diseases, smallpox, which has already been eradicated worldwide, scored the highest (average score of 2.7), followed by Covid-19 (average score of 1.6) and finally polio (average score of 1.5).
Before revealing the most important factors for each of the infectious agents, the Define concepts It is important to control, eliminate and eliminate the disease. A disease is considered under control when there is a decrease in incidence (cases per 100,000 population), prevalence (percentage of the sample population with the disease), disease prevalence (total number of deaths) or mortality (death rate per 100,000 population) ) to an acceptable number in a particular place, due to efforts to reduce it.
Elimination of a disease occurs when the infection rate reaches zero in a given area, and also as a result of efforts to control it, even if the infectious agent remains an imminent risk. We can think of reducing dengue cases as a local success, but mosquito populations Aedes aegypti, the carrier of the virus, continues to cause concern.
Finally, the disease is eradicated when there is a permanent reduction in the incidence of an infectious disease to zero, and the infectious agent is no longer able to find susceptible individuals worldwide. This is the case with smallpox.
In the study, scientists gave the maximum score for smallpox on several factors, Including an effective and safe vaccine (more than 95% effective)The absence of natural reservoirs of the virus and the huge investment in both a global vaccination campaign and case-control measures, are able to produce protection that lasts for years.
On the other hand, Covid-19 has its main strengths in favor of eliminating the global interest in controlling the disease, since The social and economic impacts, as well as demographic factors, in the past two years are still being measuredand the effectiveness of low-cost non-pharmaceutical protective measures, such as social distancing, use of masks, hand hygiene, room ventilation, and contact tracing.
However, although The development of Covid-19 vaccines has been a milestoneExisting vaccines, for the most part, Protection from disease progression, hospitalization and death, but they still can’t Prevent transmission of the virus, so they got a score of 1 in this regard.
The authors argue that another problem is reluctance to take the vaccine, which is largely due to Misleading media campaigns and fake news that were produced and spread in the pandemic.
For Nick Wilson, a researcher and professor of medicine at the University of Otago in New Zealand, and the study’s first author, the success of several Asian countries such as Hong Kong, Taiwan, Vietnam and China themselves in controlling Covid-19 shows the good part of 2020 how non-pharmacological preventive measures work when applied at scale.
In terms of Covid vaccines, Wilson believes high-tech formulas, such as those that use RNA, could be. Updated immediately for new virus variants that appear., which helps to raise the potential of protection.
but still Uncertain when immune to Corona Virus Whether it is caused by vaccination or a natural infection. “Therefore, the combination of non-pharmacological measures, as happened in New Zealand, and advances in vaccination may allow, at least in theory, to eliminate Covid-19 globally,” he says.
Even as new variants emerge, researchers are betting that the virus must be Evolve into new forms until they reach an evolutionary peak, not continuously. “The main challenge is more transmissible variants with the ability to evade the protection offered by vaccines [para erradicação da Covid], but natural selection for the most transmissible mutated forms should be largely contained by vaccines,” explains Wilson. Compare the disease to measles, more transmissible, and was considered excluded from the Americas in 2016 (in Brazil, the virus was back in circulation in 2018). “This is what we can achieve with good vaccines,” he says.
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