The Mirage of Herd Immunity, Long Covid, Cold Chain and Vaccine Scenario

Deliberately exposing the young and healthy adults to the virus while protecting the vulnerable population is a morally repugnant as well as a costly (in terms of human lives) option, writes Debananda S Ningthoujam

While the coronavirus pandemic is raging across the globe, one elusive goal that has been aspired for all over the world, and deliberately chased by a few specific countries e.g. Sweden is that of herd immunity. What is herd immunity (HI)? Herd immunity occurs when enough people develop immunity either through natural infection or a vaccine so that the outbreak or pandemic eventually peters out. Till a vaccine arrives, the only recourse we have towards herd immunity is through natural infections. But is it a desirable  and ethical option?

Deliberately exposing the young and healthy adults to the virus while protecting the vulnerable population is a morally repugnant as well as a costly (in terms of human lives) option. Interestingly, some leading scientists have recommended something akin to herd immunity. Three scientists from premier US universities have come out with a declaration in October 2020 in coordination with the American Institute for Economic Research (AIER), a think tank based in Great Barrington, Massachusetts. It has since been called the Great Barrington Declaration. The basic assumptions are that children and younger adults have a low risk from Covid-19; thus herd immunity can be achieved by exposing such people to the coronavirus while protecting the elderly and co-morbid individuals from the pandemic.

Saner voices in the scientific community have refuted these assumptions and warned of the several thousands of lives that need to be sacrificed while pursuing the mirage of herd immunity (Brooks B. Gump, US News Nov. 6, 2020). Dr John M. Barry, author of "The Great Influenza: The Story of the Deadliest Pandemic in History" writes in his opinion piece in the New York Times(Oct. 19, 2020) about three glaring omissions in the Declaration: first, it makes no mention of long-term harm to infected people in low-risk groups; second, it mentions little about how to protect the vulnerable; and third, the Great Barrington Declaration makes no mention of how many people would be sacrificed to achieve herd immunity.

 According to Barry, many recovered people suffer long-term damage in heart, lung or other vital organs. According to a study mentioned by him (JAMA Cardiology, July 27, 2020), 78 of 100 recovered adults showed signs of heart damage (nobody knows yet if this will be temporary or if this can be chronic). The so-called "focused protection" of the vulnerable also is impractical (one can prevent a child from visiting a grandparent living in another city; how about stopping him from interacting with a grandparent who lives in the same house). In addition, the cost of herd immunity through natural infections would be very high.

The Institute of Health Metrics and Evaluation (IHME), University of Washington, predicts up to 4,15, 000 US deaths by Feb. 1, 2020, even with the current restrictions in place. If they are eased, the number of deaths may shoot up to 5,71,527. According to most estimates, herd immunity can be attained only when 60-70% of the population become infected (the most optimistic calculation puts the threshold at 43%). According to CDC, only about 10% of American population has been infected (even after nearly 10 million infections out of total population of nearly 330 million). Barry calculates that by Feb. 1, even with eased protocols, only about 25% Americans would have been infected, far from the threshold for HI. The IHME estimates say that, even if HI is achieved with just 40% infections, about 8,00,000 Americans will die; the real death toll may be as high as over 1 million deaths. William Haseltine, a Harvard epidemiologist calls the HI approach through infections as recommended by the Great Barrington Declaration as "mass murder."

Extrapolate the case of US to India (1,380 million) and Manipur (approx. 30 million), and you may well imagine the human costs of using the HI (through infections) approach in either our country or our state. Sweden used the HI strategy in contrast to its neighbors (Norway and Denmark) and suffered 5 times higher deaths (per 100,000 people) as compared to Denmark and 11 times higher deaths compared to Norway.

So, we can consider pursuing herd immunity only when a safe and effective vaccine arrives on the scene.

Long Covid

As I have written in earlier columns, besides deaths, we may suffer a long-term burden in terms of post-Covid syndrome in people who have recovered from Covid-19. Many of them show damages in their hearts, lungs, blood vessels or other vital organs. Many long-haulers have reported symptoms including chronic fatigue, "brain fog" (confusion, inability to concentrate), abnormal blood clots in blood vessels, lung fibrosis etc. The most worrying thing is that such cases, of late, have been reported even in children and younger adults.

Cold chains for vaccine distribution

While the world awaits a vaccine by this year-end or early next year, not many realise about the obstacles on the way from a vaccine release to its delivery to the end-user. Many hiccups may mar the vaccine use along this route. One of the roadblocks is the substantial infrastructure needed for storage of the vaccine along the way from the manufacturer (vaccine firm) to the user (vaccination centre). Such storage facilities are called cold chains, all the way from the vaccine company to the vaccination centre. I shall dwell on this in detail in a future column.

From this angle, both the Moderna and Pfizer vaccines (mRNA-based vaccines) are unsuitable for poor, tropical countries like India as these vaccines require deep freeze facilities (-200C to -700C). These two vaccines are among the frontrunners. However, as and when they are released, they mayn't be very useful in many small towns and peripheral cities in India that lack such storage facilities. From this perspective, the Oxford/AstraZeneca vaccine seems more suitable to Indian conditions (viral vector vaccine, CoviShield, SII vaccine, 2-80C).

The current vaccine scenario

Moderna and Pfizer Inc. both claim that they would have early trial (phase-3) data by end of November 2020. Both AstraZeneca and J&J also assert that they would have enough vaccine data in this year. Any vaccine showing at least 50% protection in vaccinated individuals against COVID-19 would be considered efficacious, though the EU, WHO, and the UK set slightly different standards for vaccine approval. That is to say that there should be twice as many infections in volunteers who receive a placebo as that happen in the vaccinated group. In addition, any effective vaccine must also be very safe i.e. it mustn't cause adverse events in the vaccinated people. One can hope for at least a single registered vaccine by the first quarter of 2021. But as the saying goes, "There is many a slip between the cup and the lip."

The silver bullet for Covid-19 is an efficacious, safe, and affordable vaccine and/or drug. But we don't have it yet. But as Derek Thompson writes in The Atlantic magazine (Oct. 12, 2020), there are "bronze bullets abound." The 3 Ws and 3 Cs are some of these bronze bullets. At this critical point of the pandemic, it's we-hoi polloi, common people-who with our (in)appropriate behaviour will determine the trajectory of Covid-19 in Manipur. Once again I humbly appeal to fellow citizens to abide by the 3 Ws and 3 Cs guidelines strictly!

In addition, the public health authorities may consider a few things, if feasible: localized, focused lockdowns in specific areas, mass testing at containment zones and hotspots of infections, rapid contact tracing and isolation/quarantining of potentially infected cases/sick patients, weekly publications of Covid graphs with categories of infected people and mortalities, strengthening of healthcare facilities, timely supportive care and treatment of serious Covid (and non-Covid) cases, and clear and accurate messaging from a designated public health official (just one designated person) on a regular basis (say weekly, if not daily).

(The views expressed are the writer's own)

 

First Published:Nov. 8, 2020, 10:29 a.m.

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