Looming Third Wave: A nagging fear of a third COVID wave looms over India. Although none of us wants a fresh Covid wave in our country, there are worrying signs that warns us about a possible third wave. For the past few days, Kerala has been logging over 30,000 daily cases; other regions such as Mumbai and Delhi have also witnessed a slight rise in daily cases (News18, Aug. 28, 2021).
One intriguing thing is that the state reporting the highest surge is also the one with the highest level of full vaccinations.
We must realise that a fresh COVID wave would be the result of a complex interplay of factors: the level of susceptible population, adherence to Covid-appropriate behaviour (CAB), the pace of vaccinations, and adequate testing, tracing, treatment and healthcare facilities. This interplay may be further confounded by the rise of new variants, if any. Kerala has fully vaccinated nearly 27 per cent of its population (with two vaccine doses) but its seroprevalence is only 44 per cent (that is, nearly 60 per cent of Kerala's population is still susceptible to the virus). On the other hand, the average national seroprevalence is about 67 per cent (that is, about 33 per cent Indians are still vulnerable to COVID-19 on average) but the average fully vaccinated Indian population is just 15 per cent.
The reasons for the surge in Kerala isn't known with certainty but many experts ascribe it to violations of COVID restrictions in the recent Bakrid and Onam celebrations. One mitigating factor is that there has not been corresponding rise in hospitalisations and deaths in Kerala, possibly hinting at adequate healthcare infrastructure in the state. However, the rapid rise in infections, despite high level of vaccinations, point towards inappropriate tracing and isolation protocols. The virus does not recognise any VIP; for it, every susceptible individual is a VIP, allowing it to reproduce and infect as many hosts as possible. So the take-home lesson is that, crowding must be avoided meticulously irrespective of whether the gathering is religious, cultural, political, or academic. Both the central and state governments must enforce adequate testing, tracing, isolation, and treatment protocols to prepare for a possible third COVID wave. And, there is urgent need to scale up the healthcare infrastructure including pediatric facilities, as there are reports that claim that children would be hit hard in the third wave (please note that there are also equally assertive reports claiming the contrary). As vaccines prevent hospitalisations and deaths to a great extent (though they may not prevent infections altogether), we must ramp up vaccinations so that over 50 per cent of the eligible population gets fully vaccinated (that is, they receive two vaccine doses) in the next two-three months. This is critically important as there are many reports now which show that 1 dose has very low effectiveness against the delta variant.
There are now several contrasting reports about the third wave, differing in the timing and severity. Some warn about the impending third wave which would be quite severe. Others say that the third wave would come much later and it would be much more milder than the second wave. We may, however, err on the side of caution, and start adequate preparations, assuming that a fresh Covid wave is going to strike us soon. Let's now look at some recent models about the looming third wave in India.
Dr Jayaprakash Muliyil, epidemiologist, rules out the possibility of any significant third wave in India. But Dr Gautam Menon, Ashoka University, says that the third wave could be a "steady hill" instead of the "steep mountain" of the second wave (with steep rise and decline in cases). Whether the steady hill would turn into a full-blown wave; we've to wait and see. Several factors will determine the trajectory of the third wave, the protection from prior infections or vaccinations, rise of vaccine-resistant variants, the effectiveness of current vaccines, CAB, adequate/inadequate test, trace, isolate, treat protocols and healthcare infrastructure etc.
Profs. Ranjan and Verma, IIT Kanpur, in an earlier model, considered three scenarios. If life goes back to normal, India would see a third wave peak by October, milder than the second wave (Scenario 1). If life goes to normal and a new variant arises, there will be a peak by mid-September, which could be more severe than the second wave (Scenario 2). If stricter restrictions continue in India, the third wave would peak in late October and it would be much more milder than the second wave (Scenario 3).
Another model by Profs. Vidyasagar and Aggarwal, IIT, predicted that a third wave would peak in October 2021 and the upward curve could be seen in August. In the best-case scenario, India would see 1 lakh infections per day, while there could be 1.5 lakh new daily infections in the worst-case scenario (The News Minute, Aug. 20, 2021).
Indian Institute of Science (IISc), Bangalore, scientists led by Prof S Ganesan predicted that, if a new variant emerges, Karnataka could see 20 lakh cases between August 22 and September 10, 2021. The key findings of the study are: new variants and crowding would be main reasons for the 3rd wave; increase in vaccination rate would reduce active caseloads, hospitalisations, and deaths; vaccination pace must be doubled to reduce possibility/severity of 3rd wave; and impact of 3rd wave on children (Age 0-18) could be 13 times higher than that in 2nd wave (New Indian Express, Aug. 9, 2021).
According to a US model, India would see a 'small bump' in August, but the peak of the third wave would come in November 2021 (The Print, Aug. 3, 2021). This was a modeling study done by Dr Bhramar Mukherjee, Michigan University. She predicted that "infections are likely to be rising again with a small bump...the more prominent third wave peak appears to be on the horizon sometime around November."
However, it must be noted that, even without the emergence of new variants, the delta strain which is as contagious as chickenpox and can be passed on by vaccinated people, can still trigger the third wave, if we ignore CAB, do not scale up vaccinations (two doses), and don't enforce appropriate test-trace-isolation-treatment procedures.
A worrying development is that Karnataka has recently seen a rise in Covid cases among children (India.com; Aug. 19, 2021; last accessed, Aug. 28, 2021). 543 children were found to be Covid-positive in the state in the first 10 days of August.
The majority of the current surge in India is due to the delta variant. Although quite a few delta plus infections have been reported from parts of India, we have as yet no data to indicate that delta plus would drive the third wave. However, if we don't check the spread of the disease and ramp up vaccinations quickly, it's quite likely that 1 or more new SARS-CoV-2 variants may emerge soon. If any of these become vaccine-resistant, we may anticipate a new wave of worst COVID infections.
COVID-appropriate behaviour (CAB)
As the Kerala case has shown, crowding of any kind must be strictly prevented. Adequate contact tracing is also critical. And, the protocol for isolation especially home isolation must be immediately tweaked. The pace of full vaccinations must be scaled up as soon as possible. And, there is urgent need for sero-survey in those stated where seroprevalence data is lacking (Kerala has already initiated its own seroprevalence study).
And, there must be continuing genomic surveillance studies to track the trajectory of delta variants and the likely emergence of any new variants.
Pace of vaccinations
As has been discussed time and again in this column, to protect the population from delta variant, 2 doses of the vaccine is critical. India has to ramp up full vaccinations from the current 15% to about 50% in a targeted manner in the next 2-3 months, if possible. The situation is rather complex, we must administer 1st dose to the unvaccinated, 2nd dose to the partially vaccinated. And, as there are now reports of waning vaccine effectiveness as time passes, we must consider giving booster dose (third jab) to the elderly, immunocompromised people, and those who were vaccinated in the first phase (around January 2021). And, as more and more adults get vaccinated, the virus would find that children (below age 18) would be increasingly the most susceptible group. Therefore, we must also consider administering vaccines to the kids as soon as possible (Zydus Cadila DNA vaccine for people over the age of 12 have been already given emergency use approval, and other pediatric vaccines are also in the pipeline).
The US CDC and Oxford University have reported declining efficiency of Covid vaccines. CDC reported that vaccine protection against infections dropped from 90.6 per cent to 74.6 per cent in people aged 18-49 (The Hindu, Aug. 27, 2021). It must be noted, however, that vaccines still protect against severe disease and death. The Oxford study concluded that the protection by two doses of AstraZeneca or Pfizer vaccine declined over time. AstraZeneca's effectiveness waned from 69 per cent (14 days after 2nd dose) to 61 per cent (after 90 days). It was found that people who were infected earlier and who later got two doses of the vaccine had the best protection against future infections.
An Israel study indicated that people vaccinated with Pfizer vaccine in January 2021 have just 16 per cent protection against infection now, while in people who got vaccinated in April, the effectiveness was about 75 per cent. If vaccine potency wanes over time, those who got the first shot three months ago and are waiting for their second shot are more likely to be infected in the current wave or the upcoming third wave. And the protection in healthcare workers who got vaccinated in January would be quite low now. In addition, there are people with weak immune systems (cancer and transplant patients, those over 70 years of age, autoimmune individuals and HIV positive people etc.) who would not develop strong immunity even after a second dose. So, the elderly and comorbid cases must get their second/third shots on a priority basis. Healthcare workers who go vaccinated in the 1st phase must be considered for booster shots, if possible. And, those below 18 years must be given their shots as soon as feasible.
In addition, as vaccinated people can transmit the virus almost as well as the unvaccinated, there must be strict enforcement of CAB.
Possible measures for Manipur
We need to assume that there may be a third wave in Manipur too. Even if that may turn out to be a wrong anticipation, it's better to err on the side of caution. Accordingly, we must initiate measures to squarely face a possible third wave in our state. These may include:
Conducting immediate seroprevalence studies to understand what percent of population in Manipur and in its different districts are still susceptible to the coronavirus.
Speeding up vaccinations in a big way; aggressive vaccinations with monthly targets to cover all eligible population with first doses in the next few weeks (4-6 weeks); and targeted vaccinations of all adult population with second doses in the next 2-3 months.
Regular & repeated COVID testing in hotspots.
Enhancing the ratio of RT-PCT to Rapid Antigen Testing (RAT).
Weekly "awareness messaging" about the pandemic to the public by a designated healthcare official.
Genomic sequencing of a subset of positive cases and surveillance of the variants including the delta variant: which COVID strains are there in Manipur, where are they, and where are they moving towards; and whether any new variants are emerging.
Contact tracing and government-monitored isolation of positive cases, wherever feasible.
Boosting up healthcare provisions such as medical oxygen plants, tankers and cylinders; steroids, antifungal drugs, oxygen concentrators, ventilators, oximeters, masks, PPEs, sanitizers etc.
Strengthening of healthcare infrastructure such as construction of new COVID hospitals.
Provision of more COVID care centres (CCCs), more Covid beds and ICUs in existing hospitals
Constitution of a special taskforce for the third wave; a separate taskforce for pediatric COVID is also highly recommended.
Special provisions for kids such as pediatric hospitals, wards, and ICUs, pediatric oximeters, concentrators, and ventilators and strengthening of staff such as pediatricians and pediatric nurses and paramedical workers etc.
(The views expressed are the writer's own)