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Is Vaccination Protecting Bengal’s Elderly People From COVID-19?

Is Vaccination Protecting Bengal’s Elderly People From COVID-19?

People wait to receive their second dose of Covishield outside a vaccination centre in Kolkata, May 12, 2021. Photo: Reuters/Rupak De Chowdhuri

The successes of Israel, Scotland and Qatar in vaccinating a large part of their respective populations against COVID-19, and the consequent decrease of hospitalisation and deaths, is well accepted in scientific circles now. Similar tales of success are emerging from the US. With more than 37% of all adult Americans (and 72% of the elderly population) now fully vaccinated, it is no surprise that there is a nationwide decline of COVID-19 cases and increasing evidence of the vaccines’ protective effects. All these numbers make up real-world data beyond phase 3 trials, and their resounding success is undoubtedly one of the great achievements of modern science. Vaccines defeat COVID-19 and save lives, Period.

It is reasonable to expect that the Indian vaccination drive, although now in the doldrums due to supply failures, is also showing early signs of success. However, granular data about the efficiency of Covishield and Covaxin is largely unavailable in the public domain. The only major thing that the Union health ministry has provided is a table. And it’s a rather vague dataset, with only some numbers about ‘breakthrough infections’ — i.e. the number of vaccinated people who got infected by the novel coronavirus after receiving both doses. This is unfortunate: a country battered so badly by the pandemic must already have large amounts of raw data. All that is needed is compilation, analysis and publication. But alas.

If that had happened, would as many scientists petition the government as they did recently?

Of course, analysts can still delve into the various state bulletins for some indicators about the efficiency of vaccines. And in the case of West Bengal – now hit with a steep post-election increase of COVID-19 cases and deaths – a silver lining is indeed visible.

But first, a primer about the vaccination programme in West Bengal. As in the rest of the country, vaccination of healthcare workers and other essential staff was initiated on January 16. Although now bogged down, it initially proceeded quite well. That is not surprising: the state has consistently been one of the best in providing mass vaccinations and has a large body of experienced staff.

By April 16, more than 1.1 million people had received both doses; a month later, 8.9 million citizens had received at least one dose and around 3.7 million people had received both. According to a data-map compiled by senior government officer and prominent netizen James Wilson, 9% of the state’s population has received the first dose while 3.72% has received both doses.

Among India’s five big-population states, West Bengal’s vaccination drive is at the top, along with Maharashtra – vis-à-vis the fraction of people who have received one or both doses, adjusted for population.

It is in this context that we can try to analyse the results of the vaccination drive, based on data provided by the state health ministry.

The state’s daily bulletin offers a summary that is too brief (it would do well to emulate the reports that Kerala and Tamil Nadu have issued) – of tests, results and logistical updates from the last 24 hours. The last page has some analysis focused on the fatalities plus a bar chart, entitled ‘Fatality rate in respective age brackets and gender group’.

Snapshot of fatality analysis from the daily health bulletins. Source: West Bengal Health and Family Welfare Department

The data there is divided into six age groups – 0-15 years, 16-30 years, 31-45 years, 46-60 years, 61-75 years and 75+ years – and tells us what percentage of patients in a particular age group have succumbed to the infection thus far. The bar chart has been a regular feature of bulletins for almost a year, and provides us with some insights into whether the vaccines are protecting against severe disease, hospitalisation and death.

If the fatality rates of people aged 45-60 years, 61-75 years and 75+ years are plotted over the period of December 11, 2020, to May 17, 2021, an interesting trend emerges (see below). For the oldest population (75+), the fatality rate stayed approximately constant at around 11.2% till the end of March. Then it started to dip; a month and a half later, it has steadily decreased to 7.7%. It seems fewer elderly Bengalis are dying of COVID-19.

Decline in fatality rates among middle-aged and elderly people. The arrows point to the dates from which vaccination of frontline workers and the elderly population began. The data plotted here ends on May 11. Six days later, the decreasing trend continued.

The trend is mirrored in the 61-75 and 45-60 age groups. For the former, the fatality rate stayed steady at 4.9% from December 2020 to March 2021. Then it fell and now rests at 3.4%. The latter shows a similar pattern: around 1.7% from December 2020 through March 2021, and then a drop to 1.14% in mid-May.

Taken together, the trend is unmistakable: deaths due to COVID-19 among middle-aged and elderly people has decreased in West Bengal.

Is the decrease in fatalities due to vaccines?

Correlation is not causation. What’s more, the bulletin does not provide any data on who the dead have been in the months after vaccination started. How many of them were unfortunate enough to have succumbed before any vaccines reached them? How many got infected a few days after the first dose? How many of the deceased had genuine breakthrough infections?

There is no proper ‘control group’ here. However, the correlation is born from comparing the pre-vaccinated population (December to early March) and the increasingly vaccinated population (mid-March to the present).

The period when fatality rates in vulnerable populations started to decrease overlaps with the weeks during which many middle-aged and senior citizens might have gained vaccine-induced immunity. By the first week of April 2021, more than 5 million doses had been administered to those aged 45 years and above. (The vaccine distribution is obviously non-homogeneous, but many people in West Bengal’s urban centres have got at least the first of their jabs, and these are the same places where testing and hospitalisation is high).

Are vaccines protecting people with comorbidities?

The 45+ population also has many individuals who have comorbidities that predispose patients to more severe forms of COVID-19. In fact, that is why they got their shots early. And if the vaccines are providing some protection now, there might be a decline in the number of deaths among people with pre-existing diseases with time.

Notably, the bulletin also includes a pie chart that sums up the comorbidity status of people who have died of COVID-19. This data shows a trend that parallels the one above: from December 2020 to mid-April 2021, 84% of those who died had comorbidities. Since then, this fraction has steadily decreased to 75.7%.

While one yearns for more data, whatever is in the public domain does indicate that people with comorbidities are now coping better.

Early trends

These are of course early trends. The full effects of the vaccines will take time to become prominent, especially since 86% of the doses necessary for the 45+ age group are still pending. According to a July 2020 report published by the National Commission on Population, West Bengal has 28.4 million people age 45 years and above. So they would need 56.8 million doses for 100% coverage, of which only 7.82 million have been administered thus far. (This calculation excludes 40 million people in the 18-45 age group, most of whom have not received even one dose).

Yet, with only 14% of doses administered, there is a clear ray of hope. It is not bright enough, probably because of the lack of data, but it is encouraging nonetheless and in line with the expectations of medical logic. It is informally corroborated by state doctors, who have noted a decrease in the number of COVID-19 patients with comorbidities.

This is a sign of where the major thrust of our efforts should be: to get vaccines and to get vaccinated.

And it has to be universal: vaccination has to be for everyone, not just because it is socially just (it is) but also because it is medically essential. An attitude like “let those who can afford get the vaccine; sorry about the rest but what can done?” is naïve and only portends disaster. It will leave a large part of India’s population directly vulnerable as well as prevent the fully vaccinated population from reaping the benefits of their inoculation. (The more unvaccinated individuals there are, the more potential hosts the virus will continue to have.)

COVID-19 is a systemic disease and its consequent socioeconomic burden can cripple an entire generation. No state can afford such a catastrophe.

Anirban Mitra teaches molecular biology and biotechnology in Kolkata.

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