CME INDIA Presentation by Dr N K Singh, Admin.

“You need fuel for a fire. When there is no fuel left, which is susceptible people, then the spread of the infection can decline.” – Professor Gagandeep Kang of CMC, Vellore.

Is it True for India?

• The development of antibodies and T-cell immunity against the virus is likely to be achieved soon.
• We are marching towards herd immunity, it is continuing in the community, leading to a fall in case numbers. Maharashtra’s daily positivity rate was over 24 per cent in September; it is now below 10 per cent. On October 27, it was 9.6 per cent. (Maharashtra directly impacts India’s national caseload).
• A strong indicator of this was the rising sero-prevalence (or the prevalence of antibodies) in the Indian population (As per expert opinions).

What is a second Sars-CoV-2 wave?

• A second wave is a phenomenon of infections that can develop during a pandemic.
• First the disease infects one group of people.
• Next the infections appear to go down.
• Then the infections rise in a different part of the population, resulting in what is commonly known as a second wave of infections.

Second Wave all over Europe

• From Italy to the Czech Republic and from Belgium to Spain, much of Europe is now under some form of lockdown or curfew.
• According to WHO, on October 28, nearly 50% (201,588) of the daily new cases around the world (404,159) came from Europe.

What is the scenario in India now?

• Chief of an expert panel coordinating efforts to tackle the pandemic in the country says that in India, the new coronavirus cases and number of deaths have declined in the last three weeks and the pandemic has stabilised in most of the states.
• But in five states (Kerala, Karnataka, Rajasthan, Chhattisgarh and West Bengal) and 3-4 Union Territories, there is still rising trend.
  
  

Will India soon be in a second wave?

• No clear answer exists. We can only speculate. In Europe, we are seeing resurgence of COVID-19 cases with onset of winter.
• Festive seasons are around. Pandemic related behaviour is in declining mode. We do not know the behaviour of this unpredictable virus. Relation with winter and COVID is an unexplored sea.
• If at all the second wave hits India, it is expected in December or January. It is feared that climate will be conductive when lower temperature and by then all lockdown movements will be lifted.
• It was told that hot climate of India in summer and rainy season will be non-conductive to India, but this theory failed badly!
• We neither ignore the second wave happening nor lose the hope of COVIDOLOGY being a dead science in the near future.

Influenza Season Blues

• We know very little about co-infection or the interaction between SARS-CoV-2 and influenza.
• How does co-infection with SARS-CoV-2 and influenza affect mortality from either disease? Not clear.
• Is a patient infected with one virus more likely to contract the other? Not clear.
• Is the influenza vaccine protective against SARS-CoV-2? Not clear.
• Influenza is notoriously difficult to predict. In terms of how a large outbreak would affect the COVID-19 pandemic? Not clear.

Do rt PCR if you have Flu symptoms

• We are not in a situation where we should be making diagnoses based on clinical signs alone.
• Misdiagnosis could lead to all kinds of problems.
• Influenza and COVID-19 have different recommended treatments
• Patients with influenza are not typically told to isolate.
• Bear in mind that a diagnosis of COVID-19 or influenza alone would be insufficient to exclude the presence of another co-infecting pathogen

Post-COVID Immunity Scenario/See 4 recent studies

[1.] VERY IMPORTANT MESSAGE to the world from US study:

• The vast majority of infected individuals with mild-to-moderate COVID-19 experience robust IgG antibody responses against the viral spike protein, based on a dataset of 30,082 individuals screened at Mount Sinai Health System in New York City.
• They also show that titers are relatively stable for at least a period approximating 5 months and that anti-spike binding titers significantly correlate with neutralization of authentic SARS-CoV-2.
• Their data suggests that more than 90% of seroconverts make detectible neutralizing antibody responses.
• These titters remain relatively stable for several months after infection.
• It will be critical to understand the robustness of the antibody response in these mild cases, including its longevity and its functionality, so as to inform aerocurves, as well as to determine levels and duration of antibody titers that may be protective from reinfection.

– Published on October 28-A. Wajnberg et al., Science 10.1126/science.abd7728 (2020).

[2.] Published October 29,2020 Recent Iceland Study:

• The humoral immune response is critical for the clearance of cytopathic viruses. It is generally important for the prevention of viral reinfection.
• A relationship between a humoral immune response to SARS-CoV-2 infection and protection against reinfection by this virus has been shown in rhesus macaques only. It has yet to be established in humans.
• The low SARS-CoV-2 antibody seroprevalence in Iceland indicates that the Icelandic population is vulnerable to a second wave of infection.
• Their results indicate that antiviral antibodies against SARS-CoV-2 did not decline within 4 months after diagnosis.
• This study estimated that the risk of death from infection was 0.3% and that 44% of persons infected with SARS-CoV-2 in Iceland were not diagnosed by qPCR.

[Courtsey:Amanna IJ, Carlson NE, Slifka MK. Duration of humoral immunity to common viral and vaccine antigens. N Engl J Med 2007;357:1903-1915]

[3.] Recent UK Study:

• Their findings provide evidence of variable waning in antibody positivity over time.
• At the start of the second wave of infection in England, only 4.4% of adults had detectable IgG antibodies using an LFIA.
• Antibody positivity was greater in those who reported a positive PCR and lower in older people and those with asymptomatic infection.
• These data suggest the possibility of decreasing population immunity and increasing risk of reinfection as detectable antibodies decline in the population.

[4.] ICMR – Indian data:

The city-level seroprevalence surveys prevalence’s (in the corresponding survey period):

• Mumbai – 57% in slum areas, 16% in three other wards, from June 29.
• Delhi – 23.48%, from June 27 to July 10.
• Pune – 60.8%, from July 20 to August 5.
• Ahmedabad – 23.24%, from August 15 to August 19.

CME INDIA Learning Points

• Antibodies represent durable markers of infection, providing critical information on infection rates at a population level.
• Assessment of antibodies during a pandemic can provide important population-based data on pathogen exposure, facilitate an understanding of the role of antibodies in protective immunity.
• Whether antibodies that persist confer protection and retain neutralizing or other protective effector functions that are required to block reinfection remains unclear.
• Second wave of more serious COVID is feared all over world and some countries are already witnessing it.
• Conflicting data for strong immunity post COVID infection exists. We still do not know the exact story.
• Will further lock down help or not is equally mysterious as worldwide people are now tired of what is called the New Normal. Deprivation form normal trends of life has emerged as a significant risk of psycho-somatic disorders.

CME INDIA Tail Piece

“A second wave of infection could be a very real risk as the virus is still present in the community. We don’t know if it will be a second wave, a second peak or a continuing first wave in some countries.” – Chief Scientist of the World Health Organization Soumya Swaminathan

Further Readings:

• Published online October 22, 2020 https://doi.org/10.1016/S2213-2600(20)30508-7 Lancet Respir Med 2020. Published Online October 22, 2020 https://doi.org/10.1016/ S2213-2600(20)30508-7.
• Declining prevalence of antibody positivity to SARS-CoV-2: a community study of 365,000 adults REACT study team.medRxiv 2020.10.26.20219725; doi: https://doi.org/10.1101/2020.10.26.20219725.
• Editorial in Lancet October Engl J Med 2020; 383:1782-1784DOI:10.1056/NEJMe2028079.

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