Posted in: Modified on:
According to experts, the main reasons would be respect for health protection measures, such as wearing a mask and physical distance, and ending the end of the holiday season. But vaccination and collective immunity also contribute to this scenario.
The United States has reported about 25 million confirmed cases of coronavirus since the epidemic began, but the actual number of infections could reach 100 or 125 million people, according to Jay Bhattacharya, professor of medicine at Stanford.
” The vaccination campaign in nursing homes probably contributed to the drop in hospitalizations and deaths from Covid-19,” he believes. There is also evidence that the contaminated have a high degree of immunity for a certain time. About 21 million people also secured partial immunization after receiving at least one dose of the vaccine.
In total, this could represent almost 40% of the 330 million inhabitants, but the country is still far from the target of 85% to achieve the so-called herd immunity. Some sparsely populated states, however, come close to that mark.
Jeffrey Shaman, an epidemiologist at Columbia University, developed a model on the impact of the coronavirus, and considers that “between 50% and 70% of the North Dakota population has been infected”. An extreme case, but Shaman explains that, between the increased immunity of the population and the current respect for sanitary measures, the epidemic “should now be contained”.
Like Bhattacharya, Shaman fears that preventive measures will be less respected in the spring, when population displacement tends to increase again. Mutations of the virus must also be taken into account.
The British, Brazilian and South African variants, which are more contagious, may increase the limit necessary to guarantee herd immunity. And in the case of South Africa, it poses a more serious threat of reinfection.
Infections grew again in the fall
After a reduction in cases over the summer, infections increased in the fall in the USA. With the drop in temperatures, people began to gather in closed spaces, which increases the risk of transmission in the absence of protective measures.
Then the Thanksgiving, Christmas and New Year holidays and meetings with family or friends sparked a new wave of the epidemic.
In mid-January, the United States registered an average of more than 250,000 new cases and more than 130,000 hospitalizations per day, according to data from the collaborative platform Covid Tracking Project. Covid-19 still kills 3,000 people daily.
The spread of epidemics is linked to human behavior, recalls Natalie Dean, an infectious disease specialist at the University of Florida.
She found that the population “comes into action when the number” of infections increases in her region, and cites the examples of Florida, Texas and Arizona, three states that are very lax with preventive measures, where infections have decreased thanks to “measures politics or attitude “.
Brandon Brown, a public health specialist at the University of California, points to another reason: “the decrease in misinformation” about the pandemic, since “it is difficult to deny the reality of the more than 400,000 deaths” in the country. But, although the population is more careful with the increase in cases, the opposite happens when infections decrease, experts warn.
(With information from AFP)