According to a biosecurity expert,
Covid-19 will never become an endemic illness and will always act as an
epidemic virus.
Although the endemic disease can arise in large numbers, Raina
MacIntyre, a professor of global biosecurity at the University of New South
Wales in Sydney, said that the number of cases does not vary as quickly as the
coronavirus.
"If case numbers do change [with an endemic disease], it does
so slowly, usually over the years," she said. "On the other hand,
epidemic diseases spread rapidly over days to weeks."
To measure how quickly a disease spreads, scientists use a
mathematical equation known as the R naught (or R0). The R0 indicates how many
people will get an infection from an infected person, with Imperial College
London experts predicting the number to be higher than 3.
According to MacIntyre, if a disease's R0 is more than 1, its
spread is exponential, indicating that the virus is spreading and the
conditions for an epidemic are there.
"The public health goal is to keep the effective R below
1," she said. "The effective R is R0 adjusted by interventions such
as vaccines, masks, or other mitigations." "However, we often find
recurrent epidemic waves for respiratory transmitted epidemic infections if the
R0 is greater than one."
According to MacIntyre, this is the pattern that has been seen
with smallpox for centuries, and it is still seen with measles and influenza.
It's also the pattern that's unfolding with Covid, which has had four large
waves in the last two years.
"Covid will not magically turn into a malaria-like endemic
illness with introduced in the early for long periods," she said. "It
will continue to cause epidemic waves, driven by waning vaccine immunity, novel
variants that escape vaccine protection, unvaccinated pockets, births, and
migration," says the study.
"This is why we need a continual 'vaccine-plus' and
ventilation plan to maintain R below 1, so we can live with the virus without
major societal disruptions," MacIntyre said, adding that "additional
variants will be coming."
The World Health Organization recently warned that the next Covid
type would be even more contagious than omicron.
Covid will continue to "show the waxing and waning pattern of
epidemic diseases," according to Global Biosecurity, a Twitter account
representing a collective of UNSW research departments studying epidemics,
pandemics, and epidemiology.
The organization said, "[Covid] will never be endemic."
"It is and always will be an epidemic sickness." This means it will
seek out unvaccinated or under-vaccinated individuals and spread quickly among
them."
Pandemic, epidemic or endemic?
According to the Centers for Disease Control and Prevention in the
United States, an epidemic happens when cases arise over what is usually
expected, typically unexpected.
When a disease's growth is exponential and spreads globally, the
WHO calls it a pandemic.
In a blog post last year, experts from Columbia University's
Mailman School of Public Health explained that while an epidemic is large, it
is also often contained or expected in its spread. However, a pandemic is
international and out of control. "The difference between an epidemic and
a pandemic is the degree to which the disease has spread, not the severity of
the disease."
The United States Centers for Illness Control and Prevention (CDC)
defines endemic disease as "the constant presence or normal prevalence of
a disease or infectious agent in a population within a geographic area."
According to the American Lung Association, for Covid to become
endemic, enough people must have immune protection against it, highlighting the
need for vaccination in the virus's move away from pandemic status.
Last week, WHO Director-General Tedros Adhanom Ghebreyesus stated
that Covid might be declared a global health emergency this year if the proper
steps are taken, including tackling vaccine and healthcare inequalities.
His comments come a week after another senior whom official warned that "we will never be successful in removing the virus" and that "endemic does not mean 'good,' it simply means 'here forever.'"