Online Desk: It is remarkable in every sense – finding a vaccine for such a deadly virus in such a short time less than a year -- which usually takes decades. And like many other countries, people are streaming into vaccination centres all over Bangladesh for the jab.

People`s responses are good. And so far over 37 lakh people have been vaccinated.

So can we safely surmise that the Covid-19 pandemic is over? The answer is: It is a bit difficult to make a clear binary choice between Yes and No.  In fact, the answer is probably both. With all likelihood, Coronavirus is set to become a catch-me-if-you-can thing and remain with us for years or even decades to come, as experts now point out.

So what difference does a vaccine make in this situation? A lot.  

This is evident worldwide. Israel has seen 30% less hospitalisation. In America, already ravaged by Covid deaths surpassing 4.5 lakh casualties, the infection curve is bowing down. This matters a lot financially as hospital resources can be freed up.

So people will risk going about their routine life again. The economy will bounce back, hopefully, faster than before.

But new concerns are also arising as faster with the appearance of deadly variants. It was also not totally unexpected. Viruses are intelligent organisms which know Darwin`s evolution theory better than any other thing. They faced existential threat as Covid-19 infected people developed antibody against repeat infection. If this process continued, the virus would find no other host to attach to and thrive. So it opted for the evolutionary path and changed its protein structure to become new variants.

At least two of the variants – one originating in South Africa and the other in Brazil – are proven to be deadlier and more infectious. The Kent variant in the UK is also causing havoc.

The existing vaccines are rendered less effective against these variants. And unless the scientists summon some new ideas to find more effective vaccines, these variants will continue to cause upsets.

A lot about turning the pandemic into an endemic will depend on how fast new vaccines are found and whether the virus will by then mutate into many other variants.

But until that time we should brace ourselves and be cautious, wearing masks, observing hygiene protocols, and maintaining social distancing.

We are already in a new normal which will continue for an indefinite period—maybe a few more years or a decade or decades for obvious reasons.

Vaccinating the entire world at the same time appears to be a Herculean task never experienced by the vaccine networks across the globe. It requires extraordinary administrative strength and efficiency. Some advanced economies in Europe could not move fast even with the concerted efforts by the EU member countries.   

Vaccine nationalism and stockpiling of billions of doses by advanced countries has reduced opportunities for poor countries to get early access to the jabs. Around half of the countries of the world have yet to start inoculation.

Even if a vaccine against new variants is developed in a short time, inoculation of the new jabs will remain a challenge if they spread over many countries by that time.  

The last time the world conducted large-scale vaccination was around four decades ago against smallpox. Despite global concerted efforts led by WHO, it took two decades to declare a win in the battle against smallpox which existed for three thousand years before we saw elimination of it in the 1980s.  

So, epidemiologists find it difficult to forecast any timeframe when Covid-19 will be eradicated.

The examples they have cited to give an idea of the lifespan of a virus offer both hopes and despair. The pathogen, they say, will circulate for years, or even decades, leaving society to coexist with Covid-19 much as it does with other endemic diseases like flu, measles, and HIV.

Take the case of Spanish flu of the 1918 pandemic that killed between 50 to 100 million people. By 1920, the influenza virus was still a threat, but fewer people were dying from the disease. The flu virus has yet to get eradicated.        

Two influenza experts-- David Morens and Jeffery Taubenberger at the National Institutes of Health of USA, who co-authored an article with Anthony S. Fauci in 2009 explained how the descendants of the 1918 influenza virus have contributed to a pandemic era that has lasted the past 100 years.

"All those pandemics that have happened since — 1957, 1968, 2009 — all those pandemics are derivatives of the 1918 flu," Taubenberger told The Washington Post recently. "The flu viruses that people get this year, or last year, are all still directly related to the 1918 ancestor."

This means the flu virus continued in some form or fashion. The society too moved on.

Epidemiological studies have found that the longer the influenza virus existed in a certain community, the less lethal the sickness was.

Epidemiologists predict a similar story regarding the Covid-19 pandemic, as the vaccine will put the pathogen in the rearview mirror.