Covid-19 has spread like a wildfire, wider than SARS in 2003. In less than three months, the novel coronavirus, or Covid-19, has infected more than 75,000 people with 2,236 reported deaths as of Friday. It may nowhere be close to what swine flu did in 2009, but this virus is far more contagious.
The virus, which emerged in Wuhan, the sprawling capital of Central China’s Hubei province in December, belongs to the same family of the pathogen that causes the severe acute respiratory syndrome, or SARS.
Public health experts are concerned and believe that the virus may grow into a pandemic but nothing can be predicted.
“One can be overcautious in this kind of situations but nobody can predict anything,” said VM Katoch, a former director-general of the Indian Council of Medical Research.
And, while the number of the novel coronavirus cases appears to be stabilising in China, experts say the behaviour of the virus cannot be foreseen.
“Every virus is different. A lot depends on the way the situation evolves,” National Centre for Disease Control director Sujeet Kumar Singh said.
Pandemics happen when a new influenza virus emerges, spread in over two continents from person to person and is able to infect people easily. Since the virus is new to humans, only a few will have the immunity against the pandemic virus. It will make a lot of people sick (the Covid-19 outbreak has not yet met the official designation of a global pandemic).
“How sick people get will depend on the characteristics of the virus, whether or not people have any immunity to that virus, and the health and age of the person being infected,” said a public health expert, requesting anonymity.
According to US drug regulatory authority Centre for Disease Control (CDC), more than 80% of the people infected with the Covid-19 experience mild symptoms, 14% have severe problems like pneumonia and shortness of breath, and 5% come down with a critical condition like sepsis, multiorgan failure and respiratory failure.
All viruses behave differently and have different incubation periods — which means how long it takes for symptoms to show after someone contracts the virus. The time they remain contagious also differs.
Here are some such past pandemics:
The 1918 influenza was the most severe and deadliest pandemic of the 20th century. It was caused by an H1N1 virus. Although there is no universal consensus regarding where the virus originated, it spread worldwide during 1918-1919.
In the 1918 pandemic, mortality was high in people younger than 5 years of age, who were 20-40 years’ old and older than 65 years. The high mortality in healthy people, including those in the 20-40 age group, was a unique feature of this pandemic.
death toll of 20-50 million was reported.
Ebola virus disease
The first outbreak occurred in villages in Central Africa. The 2014–2016 outbreak in West Africa was the largest and most complex Ebola outbreak since the virus was first discovered in 1976. There were more cases and deaths in this outbreak than all others combined. It also spread between countries, starting in Guinea then moving across land borders to Sierra Leone and Liberia.
According to the US CDC: The average EVD case fatality rate was around 50%. The Ebola virus causes an acute, serious illness which is often fatal if untreated. Ebola spreads only through direct contact, such as through broken skin or mucous membranes in the eyes, nose, or mouth, and is considered less easily transmissible than Covid-19.
Death toll: 2,249
In 2009, a novel influenza A, swine-flu (H1N1), infection emerged. The virus’ circulation was realised in April. The big wave of infections in North America began early in the fall. By the time vaccine started to become available in November, the outbreak had peaked. The CDC estimated that 151,700-575,400 people worldwide died from the infection during the first year. Globally, 80% of H1N1 virus-related deaths were estimated to have occurred in people younger than 65 years of age.
It had a case fatality rate (CFR) of less than 0.1%. The pandemic began in early 2009 and started to subside by May 2010, before the WHO announced its end in August 2010.
Death toll: 151,700-575,400
Since the time it was first identified in 2012, there have been multiple outbreaks of MERS (Middle East respiratory syndrome). MERS had a case fatality rate at 34.4%, but was less contagious. To date, there have been 2,494 laboratory-confirmed cases of infection with MERS-CoV and 858 deaths. MERS has a far greater CFR than Covid-19’s, but each person infected with MERS infects only one additional person, making it much less contagious. Number of deaths reported were pegged at 2,494.
The epidemic began in early 2015 from Brazil and then spread to other parts of South America, as well as several islands in the Pacific and Southeast Asia. The World Health Organization declared a global health emergency in February 2016 due to evidence that the virus could cause birth defects, as well as neurological problems.
Influenza viruses are constantly changing, China’s lockdown of Hubei province, where the outbreak began, has allowed the world to prepare. But it hasn’t stopped the virus, with new cases emerging from all around the globe.
According to the WHO, data from China suggested that about 82% of confirmed cases had only a mild infection, about 15% were severe enough to require hospital care, and about 3% needed intensive care. Preliminary data suggest roughly 2% of people who tested positive for the virus have died. Symptoms of the coronavirus may appear in as few as two days or as long as 14 after exposure, according to the US CDC.
The WHO organised a global research and innovation meeting on February 11-12. Scientists and researchers from all over the world were invited.
“We know about the epidemiology of the Covid-19 which is that the virus belongs to the family of SARS-related coronavirus … but it seems to be more transmissible: human-to-human than the SARS or MERS coronaviruses,” WHO chief scientist Saumya Swaminathan said.
“We are yet to understand the full epidemiology in terms of how easily it spreads; how many people can be infected with one person. Initial estimates were 2-3. It has been seen that the virus has infected only 1% children under 15; the older you are, the dangerous this is,” added Swaminathan.
Commenting feature is disabled in your country/region.