New Delhi: India should strengthen its surveillance and closely monitor key Covid-19 indicators to reduce the extent of a possible third wave, Dr Soumya Swaminathan, chief scientist at the World Health Organization (WHO), has told ThePrint.
“India should now scale up its surveillance, including genomic surveillance, conduct research, data analysis and keep a close eye on certain key public health indicators,” Dr Swaminathan said, adding that “it is a responsibility of the government and public health agency”.
“One has to keep an eye on the available data at the district level such as the testing rates, test positivity rate along with other kinds of surveillance activities such as Severe Acute Respiratory Infections (SARI) surveillance and Influenza Like Illness (ILI) surveillance,” she said.
“Ensuring the availability of Covid diagnostic services in remote and rural areas will also be important, as the epidemic could be moving from large cities into smaller towns and villages.”
According to the scientist, genomic surveillance, research and analysis of available data from the first and second wave, and data on sero-surveillance will also be crucial.
The country needs to monitor its bed occupancy rate along with continuous detection of clusters, she said.
“Before any possibility of the third wave we need more research, documentation and data analysis to understand the difference between the variants, how they behave in terms of transmission, their clinical severity, vaccine responsiveness…We also need a lot of analysis on existing data on reinfection because we need to know how long people are immune for.”
Dr Swaminathan further flagged the fact that in India, cities that had a high rate of seroprevalence last year, still saw a surge this year.
“So is it that the delta variant (first found in India) was able to reinfect the same people who were infected previously, or was it the waning immunity or was it entirely the fresh population — one that had not encountered the virus before — that got infected? This is what we need to understand,” she said.
Genomic surveillance, she pointed, is very important because we have recognised the importance of the variants.
“We have the delta variant, which is much more transmissible than the original virus (that infected the Indian population last year) or even compared to the alpha variant,” she said. “We need to tailor control strategies for different geographies. For example, what works in urban slums will not work in the village settings.”
The UN health agency has named the B.1.617.1 variant of Covid-19 as a variant of interest ‘Kappa’ while the B1.617.2 variant has been dubbed as variant of concern, the ‘Delta’. Both variants were first found in India. Alpha is the B.1.1.7 variant, which was first detected in the UK in September 2020.
‘India should keep cases at a low level to control future waves’
The top WHO scientist said that it is imperative for India to keep cases at a minimum.
“In most countries that have been able to contain infections and keep them at a low level, what happens is usually the authorities identify the cluster and go around and test everyone in contact (with the cluster),” she said.
Dr Swaminathan, who was the former director general of India’s apex research institute, the Indian Council of Medical Research (ICMR), cited an example of China and South Korea.
“When they have such cases, authorities go and test hundreds and thousands of people to ensure that they are picking everybody in the cluster who is positive and then following up with the necessary health measures. That’s how you maintain the transmission at a lower level,” she said.
She warned that if the government fails to check the transmission when it is still at the low levels, lockdown becomes the only answer to break the chain.
“It is the only solution when things are at a point when the healthcare system has become too overwhelmed by the number of cases and mortality is going up. Then, only, do you need a drastic measure to cut the chains of transmission,” she said.
“A lockdown can be avoided when the warning signs are picked up in advance, at an earlier stage… At the point when there is a rising trend (of infections) but you haven’t reached the point of the system being overwhelmed or of deaths increasing.”
‘No scientific basis to say children, teens will be impacted more’
There is no scientific basis to say that children and teens will be more affected by the third wave, the WHO scientist said.
Dr Swaminathan, who is also a paediatrician, however, does not rule out the possibility of some children facing the severest of the disease. She also advises the preparation of paediatric healthcare infrastructure.
“As the vaccination programme expands, they start with the elderly. Therefore younger and younger people will be more susceptible as you start giving immunity to the older people,” she said.
“So far the variants we have seen do not have any specific effect on children. We know that children can get infected and transmit the infection, ultimately schools and colleges will need to open,” she added. “We have to remember that children get infected usually with a mild illness and it’s very rare for a child to get a severe disease.
“Strengthening paediatric intensive ICUs, training doctors and nurses, bringing in equipment, putting systems in place is a good idea for the health system but it is not because the third wave will impact children very badly,” she added.
‘Aerosol transmission should not create a panic’
According to Dr Swaminathan, who is known for her work in tuberculosis, countries have to strike a balance between creating panic and informing people by saying Covid-19 is an airborne disease.
“We should not create a panic. The virus is not flying around in the air and it cannot come in through doors and windows,” she said. “We still don’t know how many virus particles are needed to infect an individual (with Covid-19) and that probably varies from person to person. There is a lot about the immune system that we are still learning.”
She explained that there are some virus particles or droplets that come out of the mouth, which are small, light and float in air for some period of time.
“If you are in a closed setting when there is no ventilation and there are many people there in a closed room and spending prolonged time together, that too without a mask, then there is a chance of being infected,” she said.
“So it is an individual’s behaviour that can prevent people from catching the virus. Avoid crowded places, meet people outdoors and if you cannot avoid them, then you wear a good well-fitted mask that covers your nose and mouth completely.”
‘Still learning of variant detected in India’
The WHO scientist also said that the organisation is still learning about the variant first detected in India.
“Mainly from the studies coming from the United Kingdom because this variant is becoming the dominant variant there,” she said. “It is 50 times more transmissible than the Alpha variant.
“Alpha variant, first spotted in the UK in 2020, was 40-50 times more transmissible than the original Wuhan strain,” she added. “On clinical severity, it’s not clear yet and that’s where we need data from India.
“In response to vaccines, the emerging data shows that neutralising antibodies titres are reduced by several folds, around 5 to 7 times against the Delta variant… which means that you need a higher level of neutralising antibodies in order to neutralise this particular virus,” she said.
‘World may attain herd immunity if 70-80% population vaccinated’
Dr Swaminathan said that as of now, the exact level at which the world will attain herd immunity is not known but “it will be around 70%-80 per cent of the total population”.
“The more transmissible the variant, the higher the percent of people that need to be protected,” she said, while adding that “if the R0 (R naught) is 2.5, then you have to vaccinate around 66 per cent of the population to get herd immunity. It could be in the range of 70-80 per cent.”
She pointed out that right now, the global coverage is very low, probably under 5 per cent. “If you look at high income countries, and then low income countries, you will see the high difference in coverage,” she said. “Global average does not mean anything. Some countries are moving to 40 to 60 per cent of coverage while other countries are still less than one per cent.
“So what we are hoping is that there will be 30 per cent coverage in every country by the end of this year and 60 per cent by the middle of next year,” she added.
(Edited by Arun Prashanth)