The Outbreak
“Seven patients admitted in the hospital were exhibiting SARS-like symptoms.” So went the message on WeChat which is a Chinese social media app. This was sent by Dr. Li Wenliang, an ophthalmologist at the Wuhan Central Hospital on December 30th, 2019. SARS(Severe Acute Respiratory Syndrome) is a viral respiratory illness caused by SARS-COV or SARS associated coronavirus. ‘Corona’ refers to the pattern of the spike protein in the virus which resembles the corona of the sun. SARS-COV was responsible for the SARS outbreak in 2003 in Southern China which spread across 17 nations, with 8,000 people getting infected and 774 dead.
Dr.Wenliang’s message spread very fast on social media and he realized that he would pay the price for that. China, as we know, is a one party state with Communist Party of China(CPC) in complete control of the country. It has no tolerance for opposition and dissent. So the information given by Dr. Wenliang couldn’t resonate with CPC model of ruling the country. He, along with seven other doctors, was summoned by authorities for spreading rumours. The police called on the netizens to not spread or believe in rumours. Unfortunately, he contracted the virus while treating a patient infected with it and died later.
This was the sequence of events during the initial days of the outbreak. With today’s globalized world, it was a given that the virus would spread across countries. But this case was different. Almost whole world got infected with the virus and although the fatality rate for SARS-COV2 is 2.2% which is less than that for SARS or MERS (SARS-9.6% & MERS-34.4%), due to the very high infection rate, the absolute value of fatality increased a lot.
While the WHO declared COVID-19 a pandemic on 11th March, 2020, the virus had reached 114 countries infecting more than hundreds of thousands of people with more than 4,600 deaths.
Timeline of the key events following the outbreak:
· 8th Dec, 2019- First case in Wuhan(recorded)
· 31st Dec, 2019- First report of cases of Pneumonia in Wuhan
· 9th Jan, 2020- China announced the identification of a novel coronavirus as the cause
· 13th Jan, 2020- Case of a traveler from Wuhan confirmed in Thailand.
· 20th Jan, 2020- Human-to-human transmission confirmed
· 23rd Jan, 2020- Wuhan City locked down
· 29th Jan, 2020- Covid spread to all 34 provinces across China
· 30th Jan, 2020- WHO declared a PHEIC (Public Health Emergency of International Concern) alert
· 11th Feb, 2020- ICTV named virus SARS-COV 2 and WHO named disease COVID-19
· 28th Feb, 2020- WHO increased risk assessment to very high on the global level
· 11th Mar,2020- WHO declared COVID-19 as a pandemic
The Genetics of the SARS-COV2
The SARS-COV2 virus is part of the coronavirus family of viruses with it being the seventh one. Along with it, the other severe ones include SARS-COV and MERS. The mild ones include HKUI,NL63,OC43 and 229E. Coronaviruses are single stranded RNA viruses and zoonotic in nature, which means commonly affecting animals like birds, camels, pigs and bats. But they do get transmitted from animals to people sometimes.
The SARS-COV2, like its predecessor, has an outer fatty layer surrounded by spike proteins. These spikes latch on to human cells by binding to receptors called Angiotensin-converting enzyme 2 (ACE2). Then they undergo structural change by which they fuse with the human cell membrane and enter the cells. They replicate with the help of the host cell as they can’t replicate on their own. The RNA of the virus has the information for the copying process. Once inside the cell with the help of the spike protein, the virus commands the cell to produce RNA and proteins, which it needs to replicate. This process is hidden from the cell in a double-membrane compartment. The RNA copies are used in two ways. First for transmitting into next batch of viruses and the second to instruct the cell to make proteins. They newly produced virus leaves the host cell in a special compartment. Thus, several thousands of copies are made.
Covid-19 infection:
Test, Trace, Isolate
There are primarily two types of tests for COVID which are called diagnostic tests:
1.Molecular/PCR test
2.Antigen test
The Molecular/PCR test involves detection of RNA of the virus using Nucleic Acid Amplification Test like Reverse Transcription- Polymerase Chain Reaction. In this, the samples taken from back of the nose or mouth using a swab undergo a test. The first step in this test is the reverse transcription which means creating a complementary DNA from the viral RNA. This is done by adding a primer which binds with the complementary part of the viral RNA. The reverse transcriptase enzyme is utilized to extend this primer to complete the complementary DNA structure. Three steps complete the RT-PCR procedure:- Denaturation, Annealing and Extension. In the Denaturation step, the strands of the newly formed DNA are separated using high temperature reaction. Annealing involves binding a primer to one of the strands of DNA and Extension involves the utilization of DNA polymerase to extend the primer to complete the structure of DNA. There is also a TaqMan probe which also binds to the strand at one place. It consists of a fluorophore emitting fluorescence at one end and a quencher at the other end which does not allow the fluorescence to be detected at that stage. While extension, when the DNA polymerase reaches the TaqMan probe, the fluorophore gets separated through cleaving. The above process is repeated through a number of cycles till there is adequate amplification of fluorescence to detect the presence of the virus. The Indian Council of Medical Research(ICMR) recommended value of CT (Cycle Threshold) is 35 which means if the CT value is less than 35, then only the person is declared as COVID positive. This means lower number of cycles are required for detection.
The Antigen test is a rapid test where antigens (or antibody generators) are detected using a test kit under 15 minutes. The sample taken from a person is treated with a solution of salt and soap. If there is a presence of SARS-COV2 in the sample, then the antigens bind to the antibodies which are specific to the virus and are painted on the test strip. A coloured line appears on the strip which indicates the presence of the virus. But the accuracy of this test is questionable since it my might give a false negative result if enough viral antigens are not present in the sample.
There is also an antibody test which look for antibodies in the immune system which are produced in response to the virus. Antibodies may take several days or weeks to develop after an infection and may stay in the blood for several weeks or more after recovery. It is not recommended to used antibody test to diagnose an active COVID-19 infection.
After the outbreak, appropriate COVID protocols were released by the authorities in India and all over the world. The ideal scenario involved testing, tracing and isolation of the COVID patient which essentially meant preventing further infections. Unfortunately, there were gatherings taking place post the outbreak. People unaware of the seriousness of the pandemic didn’t follow the preventive measures properly.
Indian government announced a 21-day total lockdown in March, 2020. Most of the countries were in some or the other kind of a lockdown. The three preventive measures of masking, sanitizing and social distancing were put into place. Travellers were required to quarantine to mitigate the spread of the infection.
Economy vs Virus
Lockdowns naturally meant disruption in routine activities which affected the lives of millions of people around the world. While working from home became the norm for those who could do so depending on the nature of their work, this was not the case for others who had faced loss of income due to disrupted businesses. Even employees in general faced some pay-cuts due to financial constraints faced by the organizations they were working for. Many suffered from job losses.
Around 255 million jobs were lost in 2020 across the globe. According to United Nations Development Programme (UNDP) the global GDP fell by 3.3% in 2020. Migrant workers in India went back to their hometowns due to the lockdown since they were unable to make ends meet at their places of work. This led to a huge crisis in India. There was uncertainty of return of the migrants to their places of work. Decrease in migrant workers meant shortage of supply of labour force and in turn increase in wages. The migrants themselves had to face hardships by undertaking long, hazardous journeys back to their home towns. Uncertainty about their livelihoods led to anxiety and mental health issues. Thousands of migrant workers died during this period.
Economic condition across the world as per below figure:
Vaccine Race
Usually making a vaccine would take more than 10 years and cost between $200 million and $500 million. But due to the gravity of the pandemic situation the process of vaccine development was speeded up. This increased the cost but the considering the economic losses which could be brought about by the pandemic, this was worth the investment. Different stages of development and production were undertaken at the same time.
There were several companies who developed and got approval for vaccine roll out. For eg: Pfizer-BioNTech(US&Germany), Moderna(US), Oxford-AstraZeneca(UK), Johnson & Johnson(US) and so on.
UK became the first country to start administering the vaccines to its citizens using Pfizer jab.
There are three methods of vaccine development:
1. The whole-microbe method
2. The subunit method
3. The genetic method
In the whole-microbe method, one approach is to inactivate the disease-causing virus using chemicals, heat or radiation. Covaxin, the first indigenously developed vaccine in India, was made using this approach by Bharat Biotech. Also, Chinese companies SinoVac and Sinopharm used this approach. Another approach is the live-attenuated approach using a weakened virus. The third one is to use a viral vector vaccine in which a safe virus different from the one causing the disease is used as a vector to deliver subparts or proteins of the original virus to trigger an immune response. Oxford-AstraZeneca, Johnson & Johnson and Gamaleya Research Institute(Sputnik-V by Russia) developed this kind of vaccine.
The subunit method uses very specific parts of the virus that would be recognized by the immunes system. Novavax(US) developed this kind
The genetic method uses genetically engineered mRNA or messenger RNA to give instructions to the cells for making the S protein found on the surface of the SAR-COV2 virus, which ultimately triggers the immune system. Pfizer-BioNTech and Moderna developed this kind of vaccine.
Variants and Waves
Variants arise due to mutations undergone by viruses. In India, three waves of COVID-19 have come, while others countries like for eg- US,UK, etc., have seen more waves which was primarily due to the new variants coming up in each wave.
Three types of variants have been classified by WHO:-
1. Variant of Concern (VOC):- This variant can affect people and cause higher risk of severe illness or fatality. This is highly transmissible. There are five variants currently designated under this classification. Alpha or B.1.1.7(first reported in UK), Beta or B.1.351(first reported in South Africa), Gamma or P.1(first reported in Brazil), Delta or B.1.617.2(first reported in India) and Omicron or B.1.1.529(first reported in South Africa)
2. Variant of Interest (VOI):- This variant is also potentially highly transmissible, although causing less severity than VOC
There are two variants currently designated under this classification. Lambda or C.37(first reported in Peru), Mu or B.1.621(first reported in Colombia)
3. Variant of High Consequence (VOHC):- This variant is less affected by preventive measures or medical treatment.
Currently there are no such variants.
The Delta variant in India, which brought about the second wave, was the most severe with increased fatality. The health infrastructure was under enormous pressure with lack of ventilators, oxygen cylinders and beds to treat patients who were getting infected and the spread increased tremendously with cases peaking at more than 400,000 a day and daily deaths of more than 4,000.
The Future
Several experts have mentioned that SARS-COV2 pandemic will be reduced to an endemic in near future. It could take the form of a seasonal flu. Vaccines might become more affordable in near future and more drugs for treatment may be available. As far as the origin of SARS-COV2 is concerned, there is still considerable debate in the public domain and within the scientific community as to whether it leaked out of a lab in Wuhan (Wuhan Institute of Virology) or from a wet market for animals at the same place. Some suggest that the genetic features in the virus are unusual which indicates generic engineering by humans. At the same time, researchers have found out that the genome of SARS-COV2 is very similar to that of RATG13, a coronavirus that was first found in a bat. So this means natural origins of SARS-COV2 can’t be ruled out. However, RATG13’s genome is only 96% identical to SARS-COV2’s, which means that the closer relative of the virus, which passed to humans, remains unknown. Irrespective of the origins, lessons must be learnt from COVID-19. The scientific community, governments and health organizations across the globe should take preventive measures to avoid or at least reduce the probability of outbreak of such a pandemic in future. Virology institutes should be stringently monitored and the wet markets need to be effectively regulated. There should some mechanism designed to monitor the disruption of natural habitats of animals or birds and better platform needs to be provided for environmentalists to have their say. Health infrastructure should be prioritized and every country should be better prepared to face such pandemics if they occur in future.
References:-
https://www.statista.com
https://www.fda.gov
https://www.indiatoday.in
https://www.nature.com
https://www.latimes.com
https://www.oecd.org
https://www.ncbi.nlm.nih.gov
https://www.youtube.com/channel/UCGqQrz8HUV98ii7A_Pz1X_Q
https://www.youtube.com/channel/UCEPMCywJ6FPZpQ_aPEZt5JA
https://www.usglc.org
https://www.ncbi.nlm.nih.gov
https://www.orfonline.org
https://scroll.in
https://www.bbc.com
https://wellcome.org
https://www.who.int
https://www.healthcareitnews.com
https://www.nbcchicago.com
https://www.cbc.ca
IMF/BBC
