Filenews 5 October 2021
After 18 months of a social distancing pandemic, masks and lockdown, what we all want to know is when and how all that we are living will end – Although nothing can be certain, scientists have enough data to form realistic scenarios as to the evolution of the pandemic.
In a related publication in The Conversation, professor of medicine at the University of East Anglia, Dr. Paul Hunter explains that the current situation is not the first in which a coronavirus causes a deadly pandemic. It is believed that the Russian flu pandemic that occurred in 1880 and evolved into four or five waves for five years, actually came from another coronavirus, OC43. In England and Scotland, in fact, most of the deaths occurred in 1890-1891, with the OC43 virus, however, circulating to this day, but without causing any serious disease.
Existing evidence suggests that SARS-CoV-2, the coronavirus that causes COVID-19, is also here to stay, a conclusion that scientists reached a few months ago, arguing that neither vaccines nor natural disease will stop its spread.
"Although vaccines do reduce transmission, they do not prevent infection to an extent capable of eliminating the virus. Even before the onset of the Delta mutation, we saw fully vaccinated people infected with the virus and transmitting it to others. As vaccines are slightly less effective in combating the Delta variant compared to other forms of the virus, the likelihood of infection after vaccination has increased," says Dr. Hunter and adds:
"Immunity to the infection also begins to decline a few weeks after the second dose of vaccine. And since this immunity is neither absolute nor permanent, herd immunity is practically unattainable. This means that COVID-19 is likely to become an endemic phenomenon, with the daily number of cases depending on immunity and population mixing."
Other human coronaviruses cause recurrent infections on average every three to six years, while new research suggests that immune protection against the development of symptomatic COVID-19 appears to be waning. However, protection against serious disease - caused either by immunization or by physical illness - lasts much longer, while it does not seem to be lost when faced with new mutations.
Indeed, for other human coronaviruses, the vast majority of infections are either asymptomatic or like a mild cold, and the signs suggesting that COVID-19 may evolve so are already here.
Pandemic with multiple end
The end of the pandemic will vary from country to country and will depend on the proportion of the population immunized and how many people will have been infected (building the rate of natural immunity) since the start of the pandemic.
"In countries with high vaccination coverage and a large number of cases, most people will have some form of immunity to the virus and therefore COVID-19 will be less severe. And as more and more people gradually strengthen due to re-infection or an increase in immunization, we can expect an increasing proportion of asymptomatic new infections or at least mild illness. The virus will remain with us, but the disease will become part of history", says Dr. Hunter.
As the expert explains, however, in countries that have not seen many cases, but have high vaccination coverage, many are those who will remain vulnerable. "In the countries with the highest vaccination coverage worldwide, over 10% of people have not yet received the vaccine. Theoretically, anyone who has not yet been vaccinated is likely to be infected and at risk of serious illness and death (depending on their age and medical history) at any time", he stresses.
The resumption of social and economic activities in these countries will almost certainly lead to an exponential increase in infections due to the large number of people who are not immune. And as the viral load circulating increases, there will be more cases in fully vaccinated people as well, since vaccines are not 100% effective. Although COVID-19 tends to be less severe among those vaccinated, some are indeed seriously ill – and in these countries there may be a significant number of vaccinated people who will need hospitalization.
"So when these countries choose to reopen, the consequences will be significant. If this is done too early, many people will wait to be vaccinated. If it becomes too late, the effectiveness of vaccines in those already vaccinated will have begun to decline", dr. Hunter.
In any case, the most important lesson from the Russian flu is that COVID-19 will become less common in the coming months and that most countries have almost completely left behind the worst phase of the pandemic. But it is important that vaccines are also made available to the rest of the world's vulnerable populations.
It is now becoming clear that the main effect of vaccination will not be to prevent the transmission of SARS-CoV-2, but to reduce the severity of the infection the first time a person is confronted with the virus. If someone has already been through the first or second physical illness, vaccines will offer an additional, relatively little protection. For the greatest reduction in severe disease, vaccines must be made available immediately to as many people as possible.
