Many people have started dreaming about a return to normalcy and normal life following the application of Covid-19 vaccines at numerous places of the globe. But while some are viewing the vaccination drive through a dichotomous prism - life before and after getting the shots - experts are cautioning the optimists not to hurry, and instead view the whole process in terms of stage-wise scenarios. A US-based epidemiologist at the Boston University Eleanor Murray put it succinctly: "Realistically, it's definitely not going to be an on/off switch on normal", as not everything will change the second the vaccine syringe enters one's arm.
The best option is to have realistic expectations about what life would probably look like during 2021 through conceptualisation in terms of three phases. The first stage can be looked at by taking stock of what can be done once a person and his or her close friends and family members are vaccinated. The second stage can cover what can be safely done when the town, city or country one lives in achieves 'herd immunity', whereby enough people are protected against infection and the novel corona-virus cannot spark fresh outbreaks. And the third stage would be reached when 'herd immunity' is attained globally, but that is most unlikely to occur during 2021.
A critical question in this phase-wise march to freedom would be: 'Are the vaccines good at merely preventing symptomatic disease, or are they also effective in preventing transmissions and infections'? A scenario can be imagined when people are vaccinated and develop a protective immune response, but the virus can still grow inside their noses and get transmitted to other people. Although experts are optimistic about reduction in infection and transmission through vaccinations, they are not certain about the degree, as more data are needed and those can emerge from trials within a few months. Meanwhile, even inoculated people should assume that they could still get infected and pass on the virus to others. That implies they should keep on wearing masks and practice social distancing whenever unvaccinated people are around them. This should continue until the first stage ends, when one would be surrounded by people who have already been vaccinated.
But one should remember that vaccines do not work instantaneously. There should be at least two weeks' wait after the first jab and minimum one week after the second before one could skip the protections. Besides, the vaccines may not work equally well for everyone, as some people may have health issues that deter them from mounting a successful immune response; and there is no certainty that everybody receiving a shot develops a completely protective response. Although vaccines are very good at preventing severe symptoms, experts do not fully rule out the possibility of developing milder ones. The risks would however be relatively low if the surrounding friends and relatives have no underlying conditions, and do not live with unvaccinated people needing protection.
Therefore masking and social distancing should continue up to the second stage when 75 to 85 per cent of the town, city or country's population become vaccinated. The Director of the American National Institute of Allergy and Infectious Diseases Dr. Anthony Fauci estimates that this stage of 'herd immunity' would be reached in the USA around mid-fall or October 2021, depending on the virus variants, inoculation rate and other factors. However, masks would probably be one of the last things to be rolled back, as they do not have much commercial or economic cost. Once an area reaches 'herd immunity', the citizens will be able to safely return to venues like schools, cinema halls and restaurants safely, as an umbrella of immunity is created once 80 per cent of the residents are vaccinated. It should however be emphasized that as many people as possible should be inoculated for 95 or 99 per cent safety, as that is how community transmission is stopped. In that situation, domestic travels can be resumed safely, but one should put off international travels until the third stage is reached.
However, the third stage is unlikely to be reached before 2022 or later, as access to vaccines is quite unequal across the globe. Europe and North America appear to be ahead in this race, but the situation has not been so promising till now in many corners of Africa, Asia and South America. As a way out, the Covax Facility of WHO may ultimately come to the rescue. It is a mechanism that combines 190 countries including 92 low-income ones by pooling resources together for ending the pandemic faster. The facility has a target of delivering 2 billion vaccine doses within 2021 to member-states irrespective of their ability to pay.
The time taken by various countries to attain herd immunity will depend by and large on how fast they can access vaccines and the proportion of their citizens taking the jabs. There is however another critical factor in reaching that stage, which is how well the vaccines can prevent infections and transmission. A few more months would be required to get an answer to that, based on the experiences gathered over that period. If the vaccines succeed in preventing infections and transmissions alongside preventing symptomatic disease, then countries may start opening their borders to visitors if they can show proof of vaccination, in order to revive tourism sector as well as the broader economy.
When it is found that vaccinations prevent 95 per cent of infections, then those vaccinated can feel free to leave behind the so-called 'new normal', and return to the old world they had left behind at the start of 2020 after the onset of Covid-19 pandemic. But perhaps, people will have to wait until 2022 or beyond before travels to all countries can recommence. For the time being, people should continue practising the measures that are required for curbing virus transmission - masking and social distancing - which are the best means for fast-tracking a return to normality.
Dr Helal Uddin Ahmed is a retired Additional Secretary and former Editor of Bangladesh Quarterly.