Which Antibodies give you Immunity ?
Which antibodies give immunity?
WHY IN NEWS:
Out of those found infected with novel coronavirus in a serorsuvey in Pune, 85% developed neutralising antibodies.
SYLLABUS COVERED: GS 3:Health:Diseases
For PRELIMS you need to understand the connection between serosurvey’s and neutralising anti-bodies.
For MAINS take a note on concept of immunity in your Mains book.Let us dive in !
THE PROGRESS TOWARDS ‘HERD IMMUNITY’
- In other words, these people had developed immunity against the disease.
- But that is not the case.It is not true.
THE CONCEPT OF IMMUNITY
- Neutralising antibodies, like other antibodies that are created to fight the disease, are nothing but proteins.
- These are a small subset of the disease-specific antibodies that are generated once an infection has occurred.
- The neutralising antibodies become special because they have the ability to thwart the entry of the same virus inside human bodies in the future.
- The other antibodies help in fighting off the virus once the infection has already happened.
- Serosurveys, like the ones that have been conducted in Delhi, Mumbai, Pune and other cities, only look for the presence of antibodies in people.
- Their purpose is to find out whether a person has been infected with the virus or not.
- Detection of disease-specific antibodies confirms that the person had been infected with the virus in the past.
- A further test needs to be carried out to detect the presence of neutralising antibodies.
- This is what has happened in the case of Pune, the only study that has looked for neutralising antibodies.
CASE STUDY : PUNE
- The study shows that while a majority of infected people do develop immunity.
- That would mean that they are at risk of reinfection.
- Although very few cases of reinfection have been documented in the current epidemic, it cannot be ruled out.
- That is why people who have recovered from the disease are also urged to continue to take protective measures such as practice physical distancing and wearing a mask.
Which Antibodies give you Immunity ?
IS IMMUNITY PERMANENT?
- In the case of the novel coronavirus, it is not yet known whether the immunity acquired through natural infection lasts for weeks, months or years.
- In the Pune study, About half the people had generated high levels of these antibodies, while the others had relatively low levels.
- Those with a high quantity of neutralising antibodies could be expected to remain immune to the disease for a longer time.
RATE OF DECLINE
- The rate of decline varies in different diseases and individuals.
- So, in the same time that people with low neutralising antibodies see their immunity becoming ineffective, those with higher levels could still have enough to continue to fend off the virus.
- Their immune system seems to be working fine, but for whatever reason they do not create those specific proteins.
WHAT ABOUT VACCINE-INDUCED IMMUNITY?
- As in the case of naturally-acquired immunity, we do not know, as of now, how long the immunity provided by a vaccine would last against the novel coronavirus.
- That is because the vaccine is designed to trigger a strong immune response with a high fraction of neutralising antibodies.
- But since the vaccines currently under production have been under trial for only a few months, the duration of immunity they provide is not known.
- If the vaccines that are eventually approved for use do not provide long-lasting immunity, they are unlikely to have high acceptance among the general public.
IS PUNE APPROACHING ‘HERD IMMUNITY’?
- The serosurvey was conducted on about 1,650 individuals in five prabhags (each consisting of three to four municipal wards) of the city.
- Of those with antibodies, now 85% have been found to have developed immunity.
- Disease prevalence in Pune, like any other city, is not uniform.
- The findings of the study could be applied well in the small population groups .
SOURCES: IE | Which Antibodies give you Immunity ?