IAS Gyan

Daily News Analysis


19th March, 2020


Explained: What is herd immunity?

The UK’s Government Chief Scientific Adviser Sir Patrick Vallance hinted at a strategy that would allow the novel coronavirus to infect 60% of the country’s population so that a degree of “herd immunity” could be achieved.

About Herd Immunity:

-       Herd immunity refers to preventing an infectious disease from spreading by immunising a certain percentage of the population.

-       The premise is that if a certain percentage of the population is immune, members of that group can no longer infect another person.

-       This breaks the chain of infection through the community (“herd”) and prevents it from reaching those who are the most vulnerable.

-       The UK government had wanted the entire population to be exposed to the novel coronavirus infection, so that the majority could develop immunity to COVID-19.

Working of Herd immunity:

-       The scientific principle is that the presence of a large number of immune persons in the community, who will interrupt the transmission, provides indirect protection to those who are not immune.

-       To estimate the extent of spread and immunity, epidemiologists use a measure called the ‘basic reproductive number’ (R0).

-       R0 indicates how many persons will be infected when exposed to an single case.

-       Based on the available evidence from China and according to various experts, R0 COVID-19 ranges between 2 and 3.

Ways of spreading infection in community:

-       The first scenario looks at a community that is not immunised. When two infectious cases, both with an R0 value of 1, are introduced, there is a possibility of the entire community being infected, with a few exceptions.

-       In the second scenario, there may be some persons who have been immunised; and only these immunised persons will not be infected when at least two infectious cases are introduced in the community.

-       The third scenario is when the majority of the community is immunised. So, when two infectious cases are introduced, the spread can take place only in exceptional cases, like in the elderly or other vulnerable persons.

Dependence of herd immunity:

-       How effective the vaccine for a given disease is.

-       How long-lasting immunity is from both vaccination and infection.

-       Which populations form critical links in transmission of the disease?

Achievement of herd immunity:

-       The higher the R0, the higher the percentage of the population that has to be immunised to achieve herd immunity.

-       Polio has a threshold of 80% to 85%, while measles has 95%.

-       With the current data for COVID-19, experts have estimated a threshold of over 60%.

-       It means more than 60% of the population needs to develop immunity to reach the stage of herd immunity.

Challenges to herd immunity:

-       The behaviour of the pathogen is still unclear. There isn’t enough statistically significant data to estimate conclusively how many persons can get the virus from a single infected person.

-       It can take months, or even longer, to build group immunity to COVID-19.

-       While herd immunity may come about from a pandemic because the people who survive may develop immunity — they also may not.

-       Herd immunity would put a huge burden on the healthcare system. Allowing the virus to pass through the population means a surge of patients, putting pressure on existing ICU and emergency beds.

Reference: https://indianexpress.com/article/explained/coronavirus-what-is-herd-immunity-6320902/

276 Indians infected with virus abroad


With 255 Indians testing positive for novel coronavirus in Iran and another 21 in other countries, the total number of Indian nationals afflicted by the COVID-19 pandemic rose to 409.

Reference: https://www.thehindu.com/todays-paper/276-indians-infected-with-virus-abroad/article31103982.ece


Nod for 83 LCA Tejas Mk-1A

The Defence Acquisition Council (DAC) chaired by Defence Minister accorded approval for the procurement of 83 indigenous Light Combat Aircraft (LCA) Tejas Mk-1A from the Hindustan Aeronautics Ltd.

About Defence Acquisition Council:

-       Defence Acquisition council was set up by government to expedite the defence procurement process.

-       Defence minister heads DAC.

-       Now, Chief of Defence Staff is also a member of DAC.

The functions of the DAC include:

-       In-principle approval of 15 year long-term integrated perspective plan for defence forces;

-       Accord of acceptance of necessity to acquisition proposals;

-       Categorization of the acquisition proposals relating to 'buy', 'buy & make' and 'make';

-       Issues relating to single vendor clearance;

-       Decision regarding 'offset' provisions in respect of acquisition proposals above Rs. 300 crores;

-       Decisions regarding transfer of technology under 'buy & make' category of acquisition proposals;

-       Field Trial evaluation.

The Light Combat Aircraft (LCA) programme, began in the 1980s to replace India's ageing MiG-21 fighters. In 2003, the LCA was officially named "Tejas".


-       It is an Indian single-engine, delta wing, multirole light fighter designed by the Aeronautical Development Agency (ADA) and Hindustan Aeronautics Limited (HAL) for the Indian Air Force and Indian Navy.

-       It is an indigenous light-weight, multi role supersonic aircraft developed in both fighter and trainer versions. Advanced materials like composites are used in the manufacture of the Tejas to reduce weight and increase the component life.

-       It is designed to carry a veritable plethora of air-to-air, air-to- surface, precision guided and standoff weaponry.

Reference: https://www.thehindu.com/todays-paper/tp-national/nod-for-83-lca-tejas-mk-1a/article31103904.ece

Nation needs NRC, Centre tells SC

Centre arguments:

-       Preparation of NRC is a “necessary exercise for any sovereign country for mere identification of citizens from non-citizens.”

-       It was the responsibility entrusted with the Central government “to identify/detect illegal migrants and thereafter, follow the due process of law”.

-       The Foreigners Act, 1946, conferred upon the government the power to expel foreigners from India.

-       It vests the Central government with absolute and unfettered discretion, and as there is no provision fettering this discretion in the Constitution, an unrestricted right to expel remains.

What is NRC?

The National Register of Citizens (NRC) is a register of all Indian citizens whose creation is mandated by the 2003 amendment of the Citizenship Act, 1955. Its purpose is to document all the legal citizens of India so that the illegal migrants can be identified and deported. It has been implemented for the state of Assam starting in 2013–2014. The Government of India plans to implement it for the rest of the country in 2020

Reference: https://www.thehindu.com/todays-paper/tp-national/nation-needs-nrc-centre-tells-sc/article31103910.ece

‘Call data being used to improve quality’

Operators have red-flagged the fact that local circle units of the Department of Telecommunications (DoT) have been asking for call data records (CDRs) by the bulk.

Operator’s arguments:

-       The DoT unit of Delhi demanded call data records (CDRs) of the entire state for February 2, 3 and 4, 2020 and separately for specific routes in Delhi with residences of Ministers, Members of Parliament, Judge, important offices.

About Call data records:

-       A call data record of a subscriber is a string of information about that mobile phone number for a particular time period.

-       This string of information includes details such as the name of the subscriber, the details of calls made by this subscriber during a given time period, the duration of each call, whether the call terminated normally or abnormally, rough location of the caller, rough location of the call recipient and various other such details.

Laws regarding sharing of call record data:

-       The Licensing Condition No.39.20 of the Licence Agreement for Unified License stipulates that all the operators have to preserve CDRs at least for one year “for scrutiny by the licenser for security reasons”.

-       The licence condition goes on to mandate that CDRs be provided by mobile companies to the law enforcement agencies & to various courts upon their specific requests or directions, for which there is a laid-down protocol.

-       Only an officer of the rank of SP and above was authorised to seek details from telecom operators, and inform the DM of CDRs obtained every month.

Reasons behind seeking call details:

-       The data was only being collected to analyse and improve the quality of telecom services.

-       No personal details are collected.

-       There is no tracking of any phone number.

Concerns with it:

-       It may lead to allegations of surveillance, especially in a State like Delhi having numerous VVIP zones having offices and residences of Ministers, MPs, and Judges.

-       It is contrary to the top court’s judgment that held Right to Privacy as a fundamental right.

-       It is violation of the law. The law enforcement agencies alone can seek the call data records, which they have to preserve and make available but in specific cases, not for general surveillance purposes.

Reference: https://www.thehindu.com/todays-paper/tp-national/call-data-being-used-to-improve-quality/article31103912.ece