Herd Immunity

Herd immunity also called as herd effect,community immunity,population immunity or social immunity is a form of indirect protection from deadly contagious or infectious disease that occurs when a large chunk of a population becomes immune to a widespread infection,whether through previous infections or vaccination or inoculation thereby providing a measure of protection for individuals who are not immune to that particular infectious disease.In a population in which a large proportion of individuals possess immunity, such people being unlikely to contribute to disease transmission, chains of infection are more likely to be disrupted, which either stops or retards the spread of disease or flattens the curve of pandemic.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, helping to shield non-immune individuals from infection.

Individuals can become immune by recovering from an earlier infection or through vaccination for instance in India a large population is already always in contact with innumerable viruses and pathogens due to their sanitation,eating habits and handwashing practices, Some individuals cannot become immune due to critical medical reasons, such as an immunodeficency or immunosuppression like cardiac, diabetic and respiratory related patients, and for this group herd immunity is a crucial method of protection.Once a certain threshold has been reached, herd immunity gradually eliminates a disease from a population. Indians have been vaccinated to a great extent like BCG(Bacillus colmette Guerine)TB vaccine, countrywide polio vaccinations since seventies.Herd immunity does not apply to all diseases,it is vital only for just those that are contagious in nature, meaning that they can be transmitted from one individual to another.Tetanus for example, is infectious but not contagious, so herd immunity does not apply here.

The critical question is how long the pandemic will last. It will probably continue until the pathogen reaches the point of naturalisation, i.e., when it stops being dreaded and invasive .This means that the quicker the ‘herd immunity’, the faster the pandemic will end.Since we don’t have a vaccine yet, the only other way to build immunity is to do so naturally, which is happening in the recuperated cases. Herd immunity has to ramp up a level at which disease transmission will reduce in a  considerable manner or become least probable. Until then,the lockdown will ensure that the R0 value is maintained as low as possible. R0 is a critical value in the case of all invasive fatal and alien microscopic species. If it is less than 1, the disease will vanish without causing an epidemic in a large swathe of territory. As it goes above 1, the probability of an epidemic rises to a certain level.In the absence of precise data for computing the R0 of SARSCoV2, the estimated value is somewhere between 1.5 and 3.5 and is zeroing in on 2.2.There are mainly four reasons for not arriving at a precise value We will know only when the lockdown is lifted whether keeping the R0 value well below 1 for a reasonable period of time will really help us.The length of the period during which infected ones, with and without symptoms (we don’t know the length of this period yet),spread the disease will decide how best we move out of the pandemic and how much time nature will get to repair itself.

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Milan Tomic

Hi. I’m Designer of Blog Magic. I’m CEO/Founder of ThemeXpose. I’m Creative Art Director, Web Designer, UI/UX Designer, Interaction Designer, Industrial Designer, Web Developer, Business Enthusiast, StartUp Enthusiast, Speaker, Writer and Photographer. Inspired to make things looks better.

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