A year and a half after the outbreak of the Corona Virus “Covid-19” pandemic, and despite the great hopes placed on the massive vaccination campaigns against the virus that began early this year to stop its spread, many countries - including the State of Qatar and other countries - are still Middle Eastern countries are making their way towards achieving herd immunity and restoring a normal lifestyle through massive vaccination campaigns.

Without herd immunity, the virus will return to its original active path once the necessary measures and interventions are stopped.

The escalation of waves of mutated strains of the virus will also constitute an additional obstacle in the fight against transmission.

How effective will mass vaccination programs be?

The effectiveness of mass vaccination can be understood through the concept of herd immunity;

Mass vaccination improves the ability to fight the virus;

Thus, herd immunity is achieved.

In fact, when the virus encounters more people who are vaccinated, the chain of viral infection is broken and its spread stops and gradually declines.

It is worth noting that the priority of vaccination should be for the segments most vulnerable to infection with the virus to reach the herd immunity to be achieved in the areas in which they live.

 The road to herd immunity and the big difference vaccines make

The number of vaccinated and vaccinated people that must be reached to achieve herd immunity depends on several factors;

The first is the number of cloned virus known as R naught, which measures the average number of individuals who become infected;

If the number of the cloned virus is 1, this indicates that each infected person transmits the virus to one person on average, which means the stability of the epidemiological situation.

But if the number of the cloned virus is higher than 1, this indicates a mutation in the epidemic and vice versa.

safety measures

The number of cloned virus can be reduced by adhering to safety measures, such as regular hand sanitizing, mask wearing, social distancing, general closure, travel restrictions, and access to herd immunity.

Herd immunity can be achieved in natural ways by allowing the virus to infect a large proportion of the population. Although this strategy is controversial; It was tested in some countries such as England and Sweden during the first wave of COVID-19 in the spring of 2020. But this strategy was quickly dismissed; As hospitals were unable to deal with the number of infected people who need oxygen supplies and intensive care, as well as that this strategy can be very harmful if allowed even in partially fortified areas with the vaccine, because it allows room for the virus to mutate and evolve, thus avoiding acquired immunity.

The number of virus clones can be reduced by massive vaccination campaigns, and the percentage of people who need to be vaccinated to achieve herd immunity depends on how aggressive the disease is.

For example, the estimates for measles and polio were 95% and 80%, respectively.

Most estimates indicated the need to exceed 65-75% of the population vaccinated against the virus to achieve herd immunity, but with the emergence of new and more contagious strains - such as the Delta strain - caution must be taken and constantly reassessed.

The second important factor is the movement of people inside and outside the affected area, as the continued application of restrictions on movement reduces the number of cloned virus.

The State of Qatar has implemented many of the above-mentioned measures through social distancing, imposing the wearing of masks, applying quarantine to travelers, and most importantly, vaccinating a large number of the population in a short period.

How will Qatar achieve herd immunity?

The government in the State of Qatar has implemented a strict closure with obligating members of society to wear masks, and to use a mobile application to track the movement of infected individuals, and to conduct the necessary examinations on large numbers.

These measures have proven to be effective in preventing the spread of the virus and keeping the pandemic under control.

The State of Qatar has launched an early vaccination campaign to protect the most vulnerable groups first.

The number of doses already administered in Qatar has reached 3.4 million doses of COVID-19 vaccines.

If we assume that each person needs two doses of the vaccine;

This is enough to vaccinate about 54.6% of the population, and the State of Qatar is also one of the few countries that have vaccinated adolescents.

How long will herd immunity to COVID-19 last?

Recent clinical trials indicate that vaccines are safe and highly effective in preventing the most mutated types of virus, but it is still unclear how long protective immunity will last, but if the duration of immunity for vaccines similar to other corona viruses - such as the corona virus that causes syndrome Middle East Respiratory - Repeat vaccination every 2 or 3 years is necessary to maintain herd immunity.

And kinetic studies of vaccination-induced antibodies will help us to accurately predict expected vaccination schedules.

Also, vaccines that produce a homogeneous and uniform response in a population provide better long-term immunity than vaccines that produce a heterogeneous response.

But overall, a very high global vaccination ceiling and commitment to social distancing and mask-wearing will be needed to prevent the sustainable spread of the virus among the population.

Does achieving herd immunity mean that the virus is no longer a threat?

Although reaching the stage of herd immunity is protective;

It is just a very fragile cover, and its duration and continuity depend on various factors, most notably:

response to the vaccine

The type of immunity that the vaccine provides to the vaccinated determines the period during which the herd immunity remains, and the vaccine generally produces 3 types of immune response, which are the production of B cells or T cells or both.

Whereas B cells attack the virus directly, T cells target the infected cells, thus stopping virus production.

While several studies indicate that vaccines produced by Pfizer-BioNTech, Moderna, and AstraZeneca-Oxford provide immunity due to the interaction of B and T cells;

Time is needed to assess whether vaccination with any of these vaccines will provide long-term immunity.

Protecting the most vulnerable people

While refusing to receive the vaccination may put herd immunity at risk, some individuals may not be able to be vaccinated for various medical reasons such as an allergic response to the vaccine.

The biggest challenge after achieving herd immunity is to keep the most vulnerable individuals who cannot be safely vaccinated and thus protect them from viral infection.

Passenger test

Travelers pose a potential challenge or threat to herd immunity, as they transmit new mutated strains of COVID-19 to communities where the virus can escape, often through the most vulnerable individuals.

Hence, countries must screen travelers coming to them, especially those who have a high risk of exposure to infectious diseases, or who come from areas where new mutated strains have recently been discovered.

After applying the precautionary measures to control the spread of the virus at the state level, a more comprehensive strategy should be available at the global level and be the next step to achieve herd immunity all over the world in order to completely eradicate the disease.