Interview with Dr Rajiv Sarkar, epidemiologist, Associate Professor, IIPH Shillong
In the following interview Dr Rajiv Sarkar, who is an epidemiologist, shares his experience and measures to combat the coronavirus disease and ways to stop the spreading of SARS-CoV-2
Q1. Doctor, can you please explain the different variants of coronavirus spread across India?
Genomic analysis indicates that different variants of SARS CoV-2 have been circulating in India. For example, B.1.1.7, which was first identified in the United Kingdom, was dominant in Delhi and Punjab. Another variant, dubbed B.1.618 was present in West Bengal, whereas B.1.617 was dominant in Maharashtra. Since then, B.1.617 variant has become the dominant strain in India and is considered to be partly responsible for the second wave of COVID-19 in the country.
Q2. Can you shed light on how contact tracing can help slow down the spread of covid 19?
Yes, definitely! You see from the time a person gets infected; he/she takes about 4 to 5 days to develop COVID-19 symptoms. However, the person may be contagious 48 to 72 hours before starting to experience symptoms and can unknowingly infect others. Then there are asymptomatic transmitters, who although infected, may not develop any symptoms. A recent analysis estimated that asymptomatic or pre-symptomatic infected individuals account for >50% of all transmission.Now, contact tracing helps identify everyone that a person recently diagnosed with COVID-19 has been in contact with since he/she became contagious. It helps prevent further transmission of the virus by quickly identifying and informing people who may be infected and contagious, so they can take steps to not infect others. Therefore, it is first and foremost important for any person observes Covid symptoms gets tested himself at earliest.
Q3 What is aerosol? How does coronavirus spread from one person to another?
In general, aerosols are liquid or solid particles suspended in air. They can be visible, like fog, but are most often invisible, like dust or pollen.The coronavirus is released in the saliva and nasal discharge of an infected person through exhalation, talking, speaking, singing, laughing, coughing, and sneezing etc. Individuals can get infected in three principal ways:
1. Aerosols: The virus can spread in poorly ventilated and/or crowded indoor settings, where people tend to spend longer periods of time. This is because aerosols remain suspended in the air and can travel up to 10 meters.
2.Droplets: The virus spreads between people who are in close contact with each other, i.e., within 2 meters (6 feet).
3.Contaminated surfaces: People may also become infected by touching surfaces that have been contaminated by the virus when touching their eyes, nose or mouth without cleaning their hands. According to our findings, the “Three C’s” describe settings where transmission of the COVID-19 virus spreads more easily:
· Crowded places;
·Close-contact settings, especially where people have conversations very near each other;
·Confined and enclosed spaces with poor ventilation.
Q4 What safety precautions should we take before going for grocery shopping or buying food items?
What I would suggest is that, firstly people should always wear masks before going out of the house. Apart from this, people should try to go during hours when fewer people will be there.
·Maintain at least 6 feet away from others while shopping and in lines.
·Only touch products that you plan to purchase, if possible.
·Practice hand hygiene
·Do not touch your eyes, nose, or mouth with unwashed hands.
·Before entering and after exiting the grocery store or market, use a hand sanitizer.
·When you get home, wash your hands with soap and water for at least 20 seconds.
Q5 If a person has not been fully vaccinated with the COVID-19 vaccine, what precautions are still required?
Vaccine-induced immunity takes at least two weeks to properly develop after the second vaccine dose. Hence, partially vaccinated people should continue following the COVID-19 appropriate behaviour to avoid any chance of exposure to the novel coronavirus:
·Continue wearing masks
· Maintain social distancing of 2 meters (6 feet)
· Handwashing with soap and water or using a sanitizer
· Additionally, follow the three C’s – avoid (a) crowded places; (b) avoid close contact settings and; (c) avoid confined and enclosed places with poor ventilation
Q6 What kind of mask should we wear? And why is double masking necessary? Which masks are the best and worst?
Masks can be categorized into 3 types: (a) fabric/cloth masks; (b) medical/surgical masks; & (c) N95 masks. N95 masks offer the best protection. Double masking, i.e., wearing a cloth mask on top of a surgical mask could reduce a wearer’s exposure by as much as 85-95%. N95 masks can be worn by healthcare workers and for home caregivers for COVID-19 patients. For others, double masking should suffice. It is, however, important to remember that the mask should cover both the nose and the mouth.
Q7 How fast can coronavirus droplets transmit and spread?
As per the US CDC, someone who has been within 6 feet of an infected person (laboratory-confirmed or a clinically compatible illness) for a cumulative total of 15 minutes or more over a 24-hour period (for example, three individual 5-minute exposures for a total of 15 minutes in one day) is considered a close contact.Research shows that the virus can live in the air for up to 3 hours. The virus can live on surfaces like plastic and stainless steel for longer time period.
Q8 Researchers have said that people with flu virus are more likely to get sick and develop symptoms of coronavirus easily. How true is it?
Influenza (Flu) and COVID-19 are both contagious respiratory illnesses, but they are caused by different viruses. COVID-19 is caused by infection with a new coronavirus (called SARS-CoV-2), and flu is caused by infection with influenza viruses.
Because some of the symptoms of flu and COVID-19 are similar, it may be hard to tell the difference between them based on symptoms alone, and testing may be needed to confirm the diagnosis.
Q9. Some people who are infected do not show symptoms, or may not develop any- are they likely to infect others -?
Yes, there is evidence that that COVID-19 asymptomatic carriers can transmit SARS-CoV-2, and its infectivity is similar to that of symptomatic patients.
Q10 Will Covid-19m RNA vaccines work against new coronavirus variants?
There are different types of COVID-19 vaccines:
·Inactivated vaccines (e.g., Covaxin): This type of vaccine contains the killed SARS-CoV-2 virus, which is recognised by the immune system to trigger a response, without causing COVID-19 illness.
·Viral vector vaccines (e.g., Covishield, Sputnik V): This type of vaccine uses an unrelated harmless virus (the viral vector) to deliver SARS-CoV-2 genetic material. When administered, our cells use the genetic material to produce a specific viral protein, which is recognised by our immune system and triggers a response.
·mRNA vaccines (e.g., Pfizer/BioNTech, Moderna): The vaccines contain a segment of genetic material (RNA) of the SARS-CoV-2 virus, which codes for a specific viral protein. When administered, our cells use the genetic material from the vaccines to make the protein, which is recognised by our immune system and triggers a specific response.
All vaccines are safe and efficacious. Current evidence suggests that the COVID-19 vaccines (Covishield, Covaxin, Pfizer/BioNTech and Moderna) are effective against the coronavirus B.1.617 variant.
Q11 Can a person vaccinated with the both doses be infected with coronavirus?
No vaccine is 100% effective at stopping transmission or infection. There is a small risk that some fully vaccinated people will get infected. This is known as a “breakthrough infection” – and it’s entirely expected.
As per the latest data, <1% of those who have been fully vaccinated (i.e., received both doses of the vaccine) got COVID.
Q12: Can coronavirus spread be caused through nails?
COVID-19 is a new disease, and we are still learning about how it spreads. So far, SARS-CoV-2 is considered to mainly spread via inhaled droplets.
However, as fingernails can harbour dirt and germs leading to the spread of infections, it is advisable that people adhere to good nail grooming practices such as trimming nails regularly and keeping them clean.
Lastly, I would like to appeal to the people, if any of the citizens of Meghalaya observe any symptoms of Covid19, they should not hesitate to call the Covid helpline number 14410 and help us to curb the spread of coronavirus.
“As we know that the ongoing coronavirus disease 2019 (COVID-19) outbreak expanded rapidly throughout India and government interventions are undertaken constantly to mitigate the epidemic and prevent the persistence of the second wave Covid19.
However, the very need of the hour is to bring major behavioural change amongst the masses and to raise awareness about getting vaccinated to create herd immunity which might end the pandemic.”
