Dr. Shyam P Lohani

The coronavirus pandemic is becoming a raging outbreak in many countries with its second, third and subsequent waves and the stringent public health measures have contained its spread up to some extent. However, these measures, especially lockdowns and prohibitory orders, have had profound negative effects on social and economic life. And life is now at risk of becoming more unsustainable and unbearable.

Vaccine rollout
The unprecedented speed and untiring work of researchers and scientists with which vaccines were developed are commendable. Within less than 12 months after the emergence of the COVID-19 pandemic, several pharmaceutical firms took the challenge and developed vaccines that protect people from SARS-CoV-2, the virus that causes COVID-19. However, the vaccine rollout is not equitable and slower than expected due to low stocks of jabs in most places, especially in resource-limited countries. For optimal protection and prevention of vaccine-resistant strains, vaccine rollout needs to be accelerated.
A large number of the world population needs to be immune to the virus to bring this pandemic to an end. This can be achieved by either natural immunity following COVID-19 infection or vaccination. The safest way to develop immunity is with a vaccine. Vaccines are a wonderful means humanity has often relied on in the past to decrease the death toll due to infectious diseases.
Several vaccines against COVID-19 have already received approvals for either full or emergency use in many countries around the globe. Covishield and Vero Cell have been used so far in our country for its vaccination programme owing to their cold chain requirements and also approved two additional vaccines viz. Covaxin and Sputnik-V as yet. Other vaccines that are in use include vaccines from Pfizer-BioNTech, Moderna, Sinovac, and Johnson & Johnson. The mechanism of action of those vaccines differ, however, their ultimate goal is to develop immunity against COVID-19. The first type of vaccine involves the production of antibodies while the second type involves the induction of responses in memory B and T cells i.e. immune cells that store information for future reference.
It is known that immune responses differ from person to person. Anyone developing a stronger immune response to a vaccine will produce more antibodies as well as memory cells and therefore have robust immunity. But it is still not known that a stronger immune response will increase the duration of immunity. Immunity may also depend on with future variants and effectiveness of the vaccines against them. Moreover, when a person is exposed to a variant capable of eluding vaccine-induced antibodies, a vaccine might not be as effective as previously speculated.
Antibodies may wane over a period of time. Reinfection is possible once antibodies decline to a level that is no longer protective. However, it is believed that the infection is likely to be milder. Studies are still going on to determine how long it will take for antibodies to decrease to the point that they are no longer protective. In such a case, a booster dose is needed to remind our immune systems to make more antibodies against the disease.
We know that vaccines work well against COVID-19 but it is too early now to speculate how long immunity lasts. We have been fighting the pandemic for more than a year now, however, most of the vaccines were recently granted emergency use authorisation. Most of the vaccines that we have right now are two-dose vaccines. After the first dose, it has been seen a good immune response within about two weeks of that first dose. And it is only after the second dose that boosts that immune response in about after two weeks. So we have not had enough time to study long-term effectiveness of the vaccines.
Persons with asymptomatic infection or among persons several days before symptoms onset can transmit COVID-19 to others. It is important to reduce the risk of transmission of infection among healthcare personnel, first responders, and essential and frontline workers as they frequently come to close contact with patients and the public. It has already been proved that COVID-19 vaccines are among the best tools we have to end the pandemic and help return to normalcy.
Basically, vaccines teach our immune system to fight the virus. And, it has been proved that those vaccines work well with relatively few side effects. Since the vaccine rollout began in early December 2020, millions of people already received full doses of vaccines and many millions around the world received the first dose. Nepal’s vaccination campaign began from the last week of January 2021 and slightly more than two per cent of the population has received the full course of the vaccines as of now.

Less severe
The recent study of Pfizer and Moderna vaccines provides a high level of protection up to six months after the second dose. However, it does not mean vaccine protection fades up after six months. Moreover, the good news is, it is believed that even if vaccinated people contract COVID-19, their symptoms will certainly be less severe.
The duration of immunity determines how quickly we end the acute phase of the COVID-19 pandemic. The shorter the duration, the less time we will have to protect a greater number of people to stop the virus from circulating. Thus, it is important why the speed of access to COVID-19 vaccines is so critical for all the countries, and why countries who already have access to vaccines should donate any surplus doses to lower-income countries through COVAX. The delay in accessing the vaccine risks allowing the virus to continue to circulate as well as mutate to new variants which may be more infectious.
There have been several reports of vaccine breakthrough cases that strongly suggest we wear a mask, practise social distancing and wash hands frequently to prevent spreading COVID-19 to others who have not been vaccinated. Therefore, all public health measures should strictly be followed to contain the virus and protect ourselves and our loved ones.

(Prof. Lohani is the founder and academic director at Nobel College. lohanis@gmail.com)