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General Studies 3 >> Science & Technology
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COVID 19 AND ALL OF IT'S VARIANTS
COVID 19 AND ALL OF IT'S VARIANTS & TRANSMISSION
1.Background
All viruses, including SARS-CoV-2 that causes Covid-19 change over time, a phenomenon known as mutation. A virus with one or more new mutations is referred to as a ‘variant’ of the original virus, according to the World Health Organization (WHO)
2.Covid-19
2.1.Origin
As per WHO, the virus that causes Covid-19 and the one that caused the outbreak of Severe Acute Respiratory Syndrome (SARS) in 2003 are related to each other genetically, but the diseases they cause are quite different. SARS was more serious but much less infectious than Covid-19. There have been no outbreaks of SARS anywhere in the world since 2003
2.2.Severity
WHO says most people infected will experience mild to moderate respiratory illness and recover without requiring special treatment
Older people, and those with underlying medical problems like cardiovascular disease, diabetes, chronic respiratory disease, and cancer, are more likely to develop serious illnesses
According to International Diabetes Federation, “When people with diabetes develop a viral infection, it can be harder to treat due to fluctuations in blood glucose levels and, possibly, the presence of diabetes complications…Firstly, the immune system is compromised, making it harder to fight the virus and likely leading to a longer recovery period. Secondly, the virus may thrive in an environment of elevated blood glucose.”
2.3.Symptoms
People with Covid have had a wide range of symptoms reported ranging from mild symptoms to severe illness, as per Centers for Disease Control and Prevention (CDC). Symptoms may appear 2-14 days after exposure to the virus
Anyone can have mild to severe symptoms. People with these symptoms may have Covid:
1.Fever or chills 2.Cough 3.Shortness of breath or difficulty breathing 4.Fatigue 5.Muscle or body aches 6.Headache 7.New loss of taste or smell 8.Sore throat 9.Congestion or runny nose 10.Nausea or vomiting 11.Diarrhea
2.4.When is it emergency
As per the Centres for Disease Control and Prevention (CDC)
The warning signs are as follows
*Trouble breathing *Persistent pain or pressure in the chest *New confusion *Inability to wake or stay awake *Pale, gray, or blue-coloured skin, lips, or nail beds, depending on skin tone
3.Transmission
The Covid-19 virus spreads primarily through droplets of saliva or discharge from the nose when an infected person coughs or sneezes, as per WHO.
Which is why, it’s extremely important to practise respiratory etiquette (for example, coughing into a flexed elbow).
4.Vaccine effectiveness
All Covid-19 vaccines approved by WHO for emergency use listing have been through randomised clinical trials to test their quality, safety and efficacy
Covid-19 vaccines are crucial tools in the pandemic response and protect against severe disease and death
Vaccines provide at least some protection from infection and transmission, but not as much as the protection they provide against serious illness and death
5.Variants
Genomic variants of various viruses are a natural phenomenon and are found in almost all countries
The Indian SARS-CoV-2 Consortium on Genomics (INSACOG)’s (a grouping of 10 National Laboratories established by Ministry of Health and Family Welfare, Government of India) analysis of circulating Covid-19 viruses-pib
According to CDC, which developed a variant classification, there are three major categories:
1.Variant of interest (VOIs) 2.Variant of concern (VOCs) 3.Variant of high consequence
According to CDC
Variant of Concern:
It is one for which there is evidence of an increase in transmissibility, more severe diseases that require hospitalisation or death, a significant reduction in neutralisation by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures
‘Variants of concern’ include B.1.1.7 or Alpha first identified in the UK, B.1.351 or Beta first identified in South Africa, and B.1.427 or Epsilon first identified in the US. Earlier, WHO had identified the Delta variant or B.1.617.2, first found in India, as a ‘variant of concern’
When necessary, variants not otherwise meeting all criteria outlined in the definitions may be designated as VOCs/VOIs/VUMs (variants under monitoring), and those posing a diminishing risk relative to other circulating variants may be reclassified, in consultation with the Technical Advisory Group on Virus Evolution (formally called the Virus Evolution Working Group)
5.1.Reason for Variants to occur
Variants are normal part of evolution and as long as the virus is able to infect, replicate and transmit, they will continue to evolve
As per MoHFW: Not all variants are dangerous and most often than not, we don’t notice them
Only when they are more infectious, or can re-infect people, do they gain prominence. The most important step to avoid generation of variants is to reduce the number of infections
5.2.Vaccine effectiveness against variants
According to WHO
The Covid-19 vaccines that are currently in development or have been approved are expected to provide at least some protection against new virus variants because these vaccines elicit a broad immune response involving a range of antibodies and cells
Therefore, changes or mutations in the virus should not make vaccines completely ineffective
In the event that any of these vaccines prove to be less effective against one or more variants, it will be possible to change the composition of the vaccines to protect against these variants
6.Different Variants
6.1.Mu (B.1.621)
Origin:
The Mu variant was first reported in the US in January 2021, although cases only numbered in the single digits
Severity:
Mu’s severity was unknown as it affected very less people
Transmission:
Although the WHO continues to classify Mu as a ‘variant of interest’ globally, the CDC lists Mu simply as a ‘variant being monitored’. The CDC counts 10 variants in the variant being monitored group, including three once considered variants of concern: the Alpha, Beta, and Gamma strains
6.2.Lambda
Origin:
It was first documented in Peru in December 2020.
Severity:
According to data from the GISAID COVID tracking initiative,nine cases globallyt were associated with Lambda. Of these, three were in Chile and six in Argentina, reported sciencefocus.com in a September 2021 article.
Symptoms:
The main symptoms, according to the NHS, are a high temperature, a new, continuous cough, and a loss or change to your sense of smell or taste.
Transmission:
It is on the list of classified variants of interest of WHO. As per WHO, as a variant of interest, the WHO considers Lambda to have mutations with established, or suspected, implications for its transmissibility and severity, and has been detected in multiple countries
Vaccine effectiveness:
In a pre-print paper that has was not peer-reviewed, researchers found that mRNA vaccines were effective against the Lambda variant. The results of this paper suggested that vaccines in current use will remain protective against the Lambda variant
6.3. Delta (B.1.617.2)
Origin:
The Delta variant, or B.1.617.2, has been largely responsible for driving the second wave of coronavirus infections and was first identified in India. It has since mutated into the variants AY.1 and AY.2
Severity:
According to CDC
Delta variant is nearly twice as contagious as earlier variants and might cause more severe illness. It caused more serious disease than the original virus, resulting in hospitalisations in large numbers, and also had higher rates of complications, increased number of deaths
Symptoms:
Individuals with Delta variant have fever, cough, loss of taste, smell, and extreme tiredness. Sore throat, headache and diarrhea are less common
Transmission:
The greatest risk of transmission is among unvaccinated people, as per Mayo Clinic. People who are fully vaccinated can get vaccine breakthrough infections and spread the virus to others. However, it appears that vaccinated people spread Covid-19 for a shorter period than do unvaccinated people
Vaccine effectiveness:
A recently published study (conducted by several Indian scientists and those from the Cambridge Institute of Therapeutic Immunology and Infectious Disease) found that the Delta variant is eight times less sensitive to antibodies generated from Covid vaccines. It has been seen that both vaccines available in India have good protection against the delta variant. While the protection from symptomatic infection is around 70 per cent, protection from severe infections hospitalisation and death are over 95 per cent
6.4.Delta Plus (B.1.617.2.1)
Origin:
The sub-lineages AY.1 and AY.2 of Delta are called Delta Plus. Delta Plus formed as a result of Delta acquiring a mutation called K417N in the spike protein. While the WHO lists Delta as a variant of concern, the Indian government has classified Delta Plus (AY.1) as a variant of concern in the country. This mutant of Delta was first detected in Europe in March 2021, but it came to light on June 13, 2021.
Severity:
The Delta variant, first detected in India, eventually became a huge problem for the whole world
However, the Delta Plus variant, at present, is limited to smaller areas in the country
The Delta Plus variant spreads at almost 60 per cent faster rate than its predecessor Delta variant, binds more easily to lung cells and enters the cells more efficiently
Symptoms:
According to ZOE Covid study app in the UK, people reported symptoms like headaches, sore throats, runny noses, and fever
Its symptoms are that of Delta and Beta, which include cough, diarrhea, fever, head ache, skin rash, discoloration of fingers and toes. Other symptoms attributed to Delta Plus include, pain in abdomen, nausea, and loss of appetite
Transmission:
In the case of the Delta Plus variant, the Health Ministry identified three characteristics increased transmissibility; stronger binding in receptors of lung cells; and potential reduction in monoclonal antibody response
6.5.Omicron (B.1.1.529)
Origin:
It is a new variant of SARS-CoV-2 that has recently been reported from South Africa on November 24, 2021 called as B.1.1.529 or Omicron (based on Greek alphabets like alpha, beta, delta etc)
According to Ministry of Health and Family Welfare (MoHFW)’s FAQs on SARS-CoV-2 Variant-Omicron, this variant has shown a very large number of mutations, especially more than 30 on the viral spike protein, which is the key target of the immune response
Severity:
It’s not yet clear if Omicron causes more severe disease
The variant is seen to be attacking the younger population more
Symptoms:
The symptoms more commonly seen in individuals with Omicron include body aches, extreme tiredness, scratchy throat, dry cough and headache. Some individuals have high grade fever as well
Transmission:
This variant might spread more easily than other variants, including Delta
Omicron is highly transmissible, being about 1.6 times more transmissible than Delta
It has properties of immune evasion offered by previous infections with other variants of Covid-19. There is also higher chance of community spread with Omicron variant
Vaccine effectiveness:
Early evidence suggests that fully vaccinated people who become infected with the Omicron variant can spread the virus to others, as per CDC
6.6.IHU Variant (B.1.640.2)
Origins:
Scientists in France have identified a new strain of coronavirus with more mutations than the Omicron variant. The cases have been linked to travel to the African country Cameroon
Severity:
There are scores of new variants discovered all the time, but it does not necessarily mean they will be more dangerous
What makes a variant more well-known and dangerous is its ability to multiply because of the number of mutations it has in relation to the original virus.
Vaccine effectiveness:
The researchers of the study at Marseille-based Mediterranee Infection University Hospital Institute found that it also carries the E484K mutation, which could mean that the variant will be more resistant to vaccines
As per CDC, new variants of the virus are expected to occur.
-Taking steps to reduce the spread of infection, including getting a Covid-19 vaccine, are the best way to slow the emergence of new variants. -It states that vaccines reduce your risk of severe illness, hospitalisation, and death from Covid-19.
7.WHO recommendation on prevention of transmission
1.Wash your hands regularly with soap and water, or clean them with alcohol-based hand rub. 2.Maintain at least one metre distance between you and people coughing or sneezing. 3.Avoid touching your face. 4.Cover your mouth and nose when coughing or sneezing. However, WHO advises rational use of medical masks to avoid unnecessary wastage of precious resources and misuse of masks. 5.Stay home if you feel unwell. 6.Refrain from smoking and other activities that weaken the lungs. 7.Practice physical distancing by avoiding unnecessary travel and staying away from large groups of people.
8.Role of Masks
According to the CDC
Wearing a mask is an effective way to reduce the spread of earlier forms of the virus, the Delta variant and other known variants
1.People who are not fully vaccinated should take steps to protect themselves, including wearing a mask indoors in public at all levels of community transmission. 2.People who are fully vaccinated should wear a mask indoors in areas of substantial or high transmission. 3.Wearing a mask is very important if you or someone in your household 4.Has a weakened immune system 5.Has an underlying medical condition 6.Is an older adult 7.Is not fully vaccinated
