It is believed that Pandemics do eventually end, even if omicron is complicating the question of when this one will. But it won’t be like flipping a light switch: The world will have to learn to coexist with a virus that’s not going away.
By Sanjoo Thangjam
I’m not an expert apropos Coronavirus but almost two years into a pandemic that has claimed more than five million lives and affected billions more, people everywhere are finding it hard to summon the energy for it, so I thought I should write an article about it and thus, after consulting various experts, doctors, epidemiologies, I’m writing this article and in case, if there are any mistakes, please do pardon me and give me rooms to improve myself so, I wholeheartedly, welcome any suggestions, feedbacks or comments. I did refer to even Wikipedia as well.
To start with, it’s said that Coronaviruses (CoV) are a large family of viruses that cause illness ranging from the common cold to more severe diseases. A novel coronavirus (nCoV) is a new strain that has not been previously identified in humans – Coronavirus disease (COVID-19)
On November 26, 2021, WHO reached deeper into the Greek alphabet to declare Omicron a new SARS-CoV-2 variant of concern. The world’s reaction has been an unpleasant mixture of dread, fatigue, and déjà vu.
EPIDEMIC
The term epidemic derives from a word form attributed to Homer’s Odyssey, which later took its medical meaning from the Epidemics, a treatise by Hippocrates. Before Hippocrates, epidemios, epidemeo, epidamos, and other variants had meanings similar to the current definitions of “indigenous” or “endemic”. Thucydides’ description of the Plague of Athens is considered one of the earliest accounts of a disease epidemic. By the early 17th century, the terms endemic and epidemic referred to contrasting conditions of population-level disease, with the endemic condition at low rates of occurrence and the epidemic condition widespread. The term “epidemic” has become emotionally charged.
The Centers for Disease Control and Prevention defines epidemic broadly: “the occurrence of more cases of disease, injury, or other health condition than expected in a given area or among a specific group of persons during a particular period. Usually, the cases are presumed to have a common cause or to be related to one another in some way (see also outbreak).” The terms “epidemic” and “outbreak” have often been used interchangeably. Researchers Manfred S. Green and colleagues propose that the latter term be restricted to smaller events, pointing out that Chambers Concise Dictionary and Stedman’s Medical Dictionary acknowledge this distinction.
A disease outbreak is the occurrence of disease cases in excess of normal expectancy. The number of cases varies according to the disease-causing agent, and the size and type of previous and existing exposure to the agent.
Although the WHO uses the term “global epidemic” to describe HIV (“WHO HIV/AIDS Data and Statistics”. Retrieved 12 April 2020.), as HIV is no longer an uncontrollable outbreak outside of Africa, some authors use the term “pandemic”. HIV originated in Africa, and spread to the United States via Haiti between 1966 and 1972. AIDS is currently a pandemic in Africa, with infection rates as high as 25% in some regions of southern and eastern Africa. In 2006, the HIV prevalence among pregnant women in South Africa was 29%. Effective education about safer sexual practices and blood borne infection precautions training have helped to slow down infection rates in several African countries sponsoring national education programs. There were an estimated 1.5 million new infections of HIV/AIDS in 2020. As of 2020 there have been about a total of 32.7 million deaths related to HIV/AIDS since the epidemic started.
Disease outbreaks are usually caused by an infection, transmitted through person-to-person contact, animal-to-person contact, or from the environment or other media. Outbreaks may also occur following exposure to chemicals or to radioactive
A disease outbreak is the occurrence of disease cases in excess of normal expectancy. The number of cases varies according to the disease-causing agent, and the size and type of previous and existing exposure to the agent.
Disease outbreaks are usually caused by an infection, transmitted through person-to-person contact, animal-to-person contact, or from the environment or other media. Outbreaks may also occur following exposure to chemicals or to radioactive materials
EPIDEMIC
The term epidemic derives from a word form attributed to Homer’s Odyssey, which later took its medical meaning from the Epidemics, a treatise by Hippocrates. Before Hippocrates, epidemios, epidemeo, epidamos, and other variants had meanings similar to the current definitions of “indigenous” or “endemic”. Thucydides’ description of the Plague of Athens is considered one of the earliest accounts of a disease epidemic .By the early 17th century, the terms endemic and epidemic referred to contrasting conditions of population-level disease, with the endemic condition at low rates of occurrence and the epidemic condition widespread. The term “epidemic” has become emotionally charged.
The Centers for Disease Control and Prevention defines epidemic broadly: “the occurrence of more cases of disease, injury, or other health condition than expected in a given area or among a specific group of persons during a particular period. Usually, the cases are presumed to have a common cause or to be related to one another in some way (see also outbreak).” The terms “epidemic” and “outbreak” have often been used interchangeably. Researchers Manfred S. Green and colleagues propose that the latter term be restricted to smaller events, pointing out that Chambers Concise Dictionary and Stedman’s Medical Dictionary acknowledge this distinction.
A disease outbreak is the occurrence of disease cases in excess of normal expectancy. The number of cases varies according to the disease-causing agent, and the size and type of previous and existing exposure to the agent.
Disease outbreaks are usually caused by an infection, transmitted through person-to-person contact, animal-to-person contact, or from the environment or other media. Outbreaks may also occur following exposure to chemicals or to radioactive
ENDEMIC
An infection is said to be endemic (from the Greek ἐν, en, “in, within” and δῆμος, demos, “people”) in a population when that infection is constantly maintained at a baseline level in a geographic area without external inputs. For example, chickenpox is endemic (steady state) in the United Kingdom, but malaria is not. Every year, there are a few cases of malaria reported in the UK, but these do not lead to sustained transmission in the population due to the lack of a suitable vector (mosquitoes of the genus Anopheles). While it might be common to say that AIDS is “endemic” in some countries, meaning found in an area, this is a use of the word in its etymological, rather than epidemiological or ecological, form.
Human alphaherpesvirus 3 virion − a herpesvirus known to infect humans. It causes chickenpox (varicella), a disease most commonly affecting children, teens, and young adults, and shingles (herpes zoster) in adults.
For an infection that relies on person-to-person transmission, to be endemic, each person who becomes infected with the disease must pass it on to one other person on average. Assuming a completely susceptible population, that means that the basic reproduction number (R0) of the infection must equal one. In a population with some immune individuals, the basic reproduction number multiplied by the proportion of susceptible individuals in the population (S) must be one. This takes account of the probability of each individual to whom the disease may be transmitted being susceptible to it, effectively discounting the immune sector of the population. So, for a disease to be in an endemic steady state it is:
{\displaystyle R_{0}\times S=1}
{\displaystyle R_{0}\times S=1}
In this way, the infection neither dies out nor does the number of infected people increase exponentially but the infection is said to be in an endemic steady state. An infection that starts as an epidemic will eventually either die out (with the possibility of it resurging in a theoretically predictable cyclical manner) or reach the endemic steady state, depending on a number of factors, including the virulence of the disease and its mode of transmission.
If a disease is in an endemic steady state in a population, the relation above allows us to estimate the R0 (an important parameter) of a particular infection. This in turn can be fed into a mathematical model for the epidemic.
HERD IMMUNITY
Herd immunity (also called herd effect, community immunity, population immunity, or mass immunity) is a form of indirect protection from infectious disease that can occur with some diseases when a sufficient percentage of a population has become immune to an infection, whether through previous infections or vaccination, thereby reducing the likelihood of infection for individuals who lack immunity. Immune individuals are unlikely to contribute to disease transmission, disrupting chains of infection, which stops or slows the spread of disease. The greater the proportion of immune individuals in a community, the smaller the probability that non-immune individuals will come into contact with an infectious individual.
Individuals can become immune by recovering from an earlier infection or through vaccination. Some individuals cannot become immune because of medical conditions, such as an immunodeficiency or immunosuppression, and for this group herd immunity is a crucial method of protection. Once the herd immunity threshold has been reached, disease gradually disappears from a population. This elimination, if achieved worldwide, may result in the permanent reduction in the number of infections to zero, called eradication.Herd immunity created via vaccination contributed to the eventual eradication of smallpox in 1977 and has contributed to the reduction of other diseases. Herd immunity applies only to contagious disease, meaning that it is transmitted from one individual to another. Tetanus, for example, is infectious but not contagious, so herd immunity does not apply.
Herd immunity was recognized as a naturally occurring phenomenon in the 1930s when it was observed that after a significant number of children had become immune to measles, the number of new infections temporarily decreased. Mass vaccination to induce herd immunity has since become common and proved successful in preventing the spread of many infectious diseases.Opposition to vaccination has posed a challenge to herd immunity, allowing preventable diseases to persist in or return to populations with inadequate vaccination rates.
The exact herd immunity threshold (HIT) varies depending on the basic reproduction number of the disease. An example of a disease with a high threshold was the measles, with a HIT exceeding 95%.
Ultimately, the answers lies to one and all of us. Therefore, we just have to watch and see but adhere the SOP strictly though some claimed that another strain is going to come up soon and overlap the present Omicron that’s creating havoc the world all over.
(Sanjoo Thangjam is a journalist based in Imphal)