No cause for Covid alarm, but we must be on guard

We have come a long way from the chaos of the second wave of Covid-19 which ravaged our health infrastructure 18 months ago. The ‘third wave’ earlier this year also seems to have been forgotten by most of us. The scramble for the vaccine is also not there. But the recent surge in cases in China has raised an alarm once again. Should we be worried?

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Since the beginning of the pandemic, there have been close to 66 crore cases across the world, with over 4.4 crore in India. China is witnessing an unprecedented increase in cases. In the last seven days, over 34 lakh people got fresh infection across the world. India has been seeing a limited number of cases for the last many months with just over 1,000 cases in the last seven days. But in some countries, there has been an upward trend of cases. Japan has had over 2.5 million infections so far this month and South Korea 1.2 million.

Though the numbers of hospitalisations and deaths have remained low, infections have resurfaced at many places. It has been estimated that more than 60 per cent of China and 10 per cent of world’s population are likely to be infected in the next three months.

China has had a ‘zero-Covid’ policy since the beginning of the pandemic. A strict protocol was in effect, with a complete isolation of positive cases and strict travel restrictions. With the population getting restive following a spate of new cases in some provinces, China opened up the restrictions, letting the pandemic take its natural course.

This was done despite warnings from scientists and analysts who feared an increase in infections since the vaccination had achieved only 50 per cent penetration and the lack of earlier infections had not generated natural immunity. The virus was already spreading ‘intensively’ in China before the authorities relaxed restrictions on December 7, the World Health Organisation had pointed out recently.

A recent study by researchers in Hong Kong had predicted that 684 people per million would die if China reopened without a mass vaccination booster campaign and other measures. That would add up to a close to a million deaths over the course of the next few months. Airfinity, a health risk analysis firm, in its model released in late November had projected between 1.3 million and 2 million deaths in China if the government abruptly ended its zero-Covid policy. An epidemiologist from China had also projected remarkably similar figures if China were to have a resurgence of infection.

In the last few days, we have seen a dramatic increase in the number of cases being diagnosed in China, with ICUs and funeral homes getting overwhelmed. According to a Chinese epidemiologist, the doubling rate of cases in China is not even days now as infections are doubling in hours. The Institute for Health Metrics and Evaluation, a global health research institute at the University of Washington in Seattle, recently projected that China’s Covid-19 death toll would spike to more than three lakh by April.

Based on these projections, China could see more than one million coronavirus deaths in 2023. The populations at greatest risk in the world are those that have avoided a lot of transmission and have gaps in vaccination.

China’s Covid-19 surge is being driven by the BF.7 Omicron sub-variant whose full name is BA.5.2.1.7. It is a sub-variant of Omicron variant BA.5.1 which had caused the last wave in India earlier this year.

As SARS-CoV-2 spread, and mutated, it led to a number of variants, such as Alpha, Delta and Omicron. These variants further went through mutations, leading to the development of new sub-variants. The development of variants is a natural process with viruses like the Covid-19 virus. The longer the virus stays in susceptible hosts, more the chances of the development of mutations, some of which can give an advantage to the virus, like it escaping vaccine-induced immunity, it spreading faster or it causing less or more severe disease.

Though the new variant is primarily driving the surge in China, it has also been found in Denmark, Germany, France and the USA. The BF.7 Omicron sub-variant has the “strongest infection ability”; each infected individual can pass it on to over 10 persons. The mutations in BF.7 give it some immune-evasive abilities — it can escape immunity from vaccine or previous infection.

Where does India stand today? Around 70 per cent of our population has been fully vaccinated till now, and a large number of people have developed immunity from natural infection. Some experts believe that around 90 per cent of India’s population has hybrid immunity. Moreover, India’s vaccines were more effective, too. Covishield provided 94 per cent protection against severe disease and Covaxin 78 per cent, while the Chinese vaccines had lower protection — 73 per cent with Sinopharm and 66 per cent with CanSino.

India had first detected the BF.7 sub-variant in a sample taken in July and since then, there have been only a handful of cases of this variant in the country. Additionally, the latest genome sequence in India of the cases (from the November 30 samples) did not show any presence of BF.7.

However, the situation can change and only a continuous genomic surveillance will show if BF.7 becomes the predominant variant. Additionally, there remains the possibility of new variants developing in the coming months. We have to accept that Covid-19 is here to stay. The elderly and those with comorbidities remain at risk to developing severe disease. Therefore, we need more testing and genome sequencing. That is exactly what the government has initiated. There is going to be a testing of international arrivals as well.

One aspect which has got neglected in India is the precaution dose or the booster dose. Data shows that around only one-fourth of the population has received a booster shot. This compares poorly with countries like Japan (100 per cent), South Korea (80 per cent) and Australia (75 per cent).

Some experts suggest that we may require yearly booster shots with the vaccine modified according to the prevalent strain.

Secondly, taking as much precautions as possible should be the norm. Using a mask in a crowded environment should be followed, so should the hand hygiene and social distancing be practised. At the individual level, symptoms like fever and cough should not be ignored. Though currently there is no cause for alarm, we should remain on guard.