When a new epidemic explodes onto the
scene, experts look for two main numbers: how many people each patient will
infect and how many people will die from the disease. To do this we plot the
daily number of cases in ‘X axis’ and the number of cases since the first case
in ‘Y axis’ on a graph. This helps them plot an arc for the outbreak: how far
it will likely spread before a vaccine is rolled out or enough people who have
recovered from the illness with virus-fighting antibodies in their system build
up "herd immunity" against it.
The "curve" researchers are talking about refers to the
projected number of people who will contract COVID-19 over a period of time.
This is not a hard prediction of how many people will definitely be infected,
but a theoretical number that's used to model the virus' spread. The curve takes on different shapes, depending on the
virus's infection rate. It could be a steep curve, in which the virus spreads
exponentially (that is, case counts keep doubling at a consistent rate), and
the total number of cases skyrockets to its peak within a few weeks. Infection
curves with a steep rise also have a steep fall; after the virus infects pretty
much everyone who can be infected, case numbers begin to drop exponentially,
too. A flatter curve, on the other hand, assumes the same number of people
ultimately get infected, but over a longer period of time. A slower infection
rate means a less stressed health care system, fewer hospital visits on any
given day and fewer sick people being turned away. So flattening this
curve means slowing how fast the virus moves through the community.
Cases might appear in just a trickle at first but, once countries
crack the 100 mark, the virus seems to either explode rapidly – such as in
China initially, and then Iran, Italy, the US, and Spain – or slow to a flatter
line as has been recorded elsewhere including Singapore and Hong Kong. Thus
these two sets of countries present two different shapes of the curve.
In less than a month, the global number of confirmed COVID-19
cases doubled from about 75,000 cases on Feb. 20 to more than 153,000 on
March 15. In Italy, for example — the country with the worst COVID-19 outbreak
outside of China — confirmed cases doubled from 10,000 to 20,000 in just four
days (March 11 to March 15).
This rapid growth rate in Italy has
already filled some hospitals there to capacity, forcing emergency rooms
to close their doors to new patients, hire hundreds of new doctors and request
emergency supplies of basic medical equipment, like respirator masks, from
abroad. This lack of resources contributes, in part, to the outsize COVID-19
death rate in Italy, which is roughly 7% — double the global average.
By limiting opportunities for the virus to
jump from person to person – by adopting "social distancing" measures
(such as staying 1.5 metres away from others and avoiding public spaces) as
well as improving hygiene and isolating those infected or exposed countries
like Singapore and Hong Kong have stretched out the spread of COVID-19 over
time, giving doctors, economies (and vaccine-makers) space to breathe.
In India we are right now is at a very crucial
juncture; if the curve keeps climbing, we will see a surge of cases needing
medical intervention all at once and hospitals will likely run out of
life-saving machines such as ventilators, which have been critical in treating
patients stricken by more serious cases of the respiratory illness. That would
push up the death toll and force impossible triage choices like the ones
already facing doctors on the frontlines of the Italian outbreak (where an age
limit has even been proposed in intensive care wards to free up beds for a
growing number of younger patients in their 40s and 50s).
Historical perspective
During the world's last severe pandemic, the 1918 Spanish flu, the
US city of Philadelphia took 14 days to mount a public health response after
its first case, even pressing ahead with a big public march. St Louis,
meanwhile, cracked down on people's movement and gatherings within just two
days of the influenza strain entering its borders. By the end of the crisis,
its death toll was less than half of Philadelphia's.
So nations that moved fast to test and track suspected cases and
then brought in tough social distancing or containment measures along the lines
of the St Louis model have already seen their infection growth fall, even after
rapid early spread.
Countries from China and Italy to the US and Israel are turning to
increasingly medieval methods to stem the tide of the pandemic, closing
borders, raising barricades and shutting down much of daily life such as
restaurants and workplaces. Other countries like Singapore and Taiwan have
brought their caseloads under control by getting ahead of the curve early
rather than bringing in lock-downs later, with more testing, forensically
tracing cases back to other people who may have been exposed and making social
distancing the norm.
Lock down or Surveillance
China's Communist government did something without precedent in
modern times – it locked down cities and transport across huge swathes of the
country, grounding tens of millions. Factories shut down. Schools and offices
closed. Streets emptied. At the time, such a move seemed
unthinkable in a Western democracy but numbers coming out of China today show it
appears to be working. China was clocking up more than 3000 new cases a day in
early February. By mid-March, that number had fallen to less than 30.
In Italy, the government was at first reluctant to impose such
draconian measures on its densely populated cities. Should it really turn
soccer fans away from matches? Or close bars, order people back into their
homes from piazzas? But the blockades in the north, where the outbreak began,
failed to stop infections leaking into the rest of the country – and beyond.
Now Italy has gone into its own style of lockdown followed quickly by Spain,
France, Belgium, Netherlands and Germany, as cases in those nations also
rise.
China and South Korea – have gone further than just lock-downs.
Knowing most infections so far have come from close contact in hospitals or family
groups, those with (and sometimes without symptoms) are taken out of their
homes and put into hospital isolation instead.
Both countries, including success stories such as Singapore, Hong Kong and
Taiwan, have also been aggressively hunting for cases – temperatures are taken
before entering any building. If you have a fever, you must roll up to a
specialized clinic or "drive-through" for testing.
South Korea interestingly saw cases erupt within a religious sect
and quickly deployed particularly exhaustive detective work to track down close
contacts of known cases– famously using CCTV to trace people back to a specific
bus or taxi and even prosecuting those who lied about their movements.
Part of the challenge facing world leaders is balancing the threat
of the virus against the huge disruption of containment, which experts warn
could bring its own health costs.
In the midst of all this India has managed
remarkably well by testing for the suspects at entry points - airports and sea ports and subsequently
quarantining them and their immediate contacts for 14 days. Much as I would
like to believe that we will be able to flatten the curve but considering our
1.3 billion population, our population density in the urban slums and hot spots
and our ignorance of the poor and carelessness of the rich, we can go the other
way too!
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