Corona virus infection depends upon
(1)face to face contact with patient (decides viral load),so putting the mask will protect.
(2)immunological response of the individual(that’s why many are asymptomatic).
(3)lockdown avoids contact between patients.But one needs to keep 18 months of lock down to completely flatten the virus spread.This number has been extrapolated from Imperial college study UK.
(4)R0 is the ability of virus to spread in community(especially when nobody has any protection against it)
If R0 >1 then it will cause epidemic (even 1.01).
If R0 <1 it will extinct the virus.(reason ofLockdown).
If R0 = 1,disease is endemic for some time till new unimmunised population surfaces.Thats why every body is scared of second wave.
If 40% population develops immunity against H1N1 that will cause herd immunity.The R0 of H1N1 is 1.3.We know that R0 of corona is 2.3-2.4 so we need 60% population to be immunised or exposed for herd immunity.
This herd immunity will come once we allow population to be exposed.India has about 35.3% population in 0-14 years,46 % from14-40 years of age.Almost 80% population is between 0-40 years.Once children start going to school & people start going to work,there is fair chance for them to get natural immunity & hence herd immunity.Till this time >60 years if age & <5 years of age should be in REVERSE QUARANTINE meaning these people should protect them selves from catching infection.
Once vaccine is available then they have chance to be protected.It requires a huge commitment from community.
More than 450 people died of swine flu in India when it first broke out in 2009. More than 13,000 people were infected with the virus. The states with the highest number of swine flu deaths in 2009 included Maharashtra, Karnataka and Gujarat. The virus is thought to have killed more than 1,200 people around the world.