Mahmoud Mutawa – Lima:
“Many families will lose their loved ones.” With these poignant words, British Prime Minister Boris Johnson came out in a televised speech in mid-March to announce his country’s plan to confront the new Corona virus, after which the term “herd immunity” or “immunity to infection” emerged as an optimal strategy in confronting the ongoing pandemic. What is herd immunity? How did the world reach it? Has it actually been applied, whether in the current crisis or throughout history? How were the results? What are its adverse results and side effects? Questions like these and more arose at the end of Johnson’s speech, amid a state of anticipation for the results of this strategy in Britain, which quickly collapsed according to a statement issued by the United Nations, amid the widespread spread of the virus that infected Johnson himself!
What is herd immunity?
The idea of “herd immunity” (in English: herd immunity) is based on living life normally, such that most members of society are infected with the virus, and thus their immune systems recognize it and then fight it if it tries to attack them again. However, specialists warn against this strategy, which causes a huge rise in the curve of infections, and an inability in the medical sector to care for the infected in light of hospitals being flooded with patients.
What does science say?
Herd immunity, from a scientific standpoint, is a form of indirect protection from an infectious disease. It occurs when a large percentage of the population acquires immunity to a specific infection, either due to previous infection or vaccination, which provides protection for individuals who do not have immunity to the disease. If a large percentage of the population possesses immunity to a specific disease, it helps prevent these people from transmitting the disease, and thus chains of infection are likely to stop, leading to stopping or slowing the spread of the disease. The greater the proportion of immune individuals in a community, the less likely individuals without immunity will be to interact with people who transmit the disease, which helps protect them from infection. Individuals may develop immunity either after recovery from an early infection or through vaccination, but some individuals cannot develop immunity for medical reasons, such as immunodeficiency or immunosuppression; Therefore, herd immunity is important for this group of individuals, as it is considered a crucial means of protection for them. When a certain threshold is reached, herd immunity gradually eliminates the disease from the population, and if the disease is eliminated worldwide, it may lead to a permanent decline in the number of infections until it reaches zero, at which point it is called eradication.
Does he have historical precedents?
Herd immunity established through vaccination contributed to the eradication of smallpox in 1977, and also contributed to reducing the spread of many other diseases, but herd immunity cannot be applied to all diseases, and can only be applied to communicable diseases, meaning that the disease is able to be transmitted from one person to another. For example, tetanus is contagious and not contagious, so herd immunity cannot be applied to it. Mass vaccination to create herd immunity has become common since then and has proven successful in preventing the spread of many infectious diseases. Opposition to vaccination has challenged herd immunity, allowing preventable diseases to continue to occur or re-emerge in communities with inadequate vaccination rates.
The dangers of herd immunity
Vaccines are usually imperfect, as some individuals’ immune systems may not generate a sufficient immune response to vaccines to provide long-lasting immunity. Therefore, some of those who received vaccines may be immunocompromised. Vaccine contraindications may also prevent some individuals from becoming immune, so in addition to not being immune, the individual may be at greater risk of developing complications from the infection because of their medical condition, but they may still be protected if a large proportion of the population is immune. High levels of immunity in a specific age group may lead to herd immunity for other age groups. Therefore, vaccinating adults against whooping cough reduces the incidence of whooping cough in infants who are too young to be vaccinated and who are considered to be at greater risk of complications from the disease. This is especially important for family members, who account for most transmission to young infants. Herd immunity itself also exerts evolutionary pressure on some viruses, affecting viral evolution, as it encourages the production of new strains, referred to as escape mutants, that are able to escape herd immunity and spread more easily. At the molecular level, viruses escape herd immunity, which occurs when mutations accumulate in the part of the virus genome that encodes the virus’s surface antigen, usually a protein from the viral capsid, leading to a change in the viral epitope.
Has it been applied during the current crisis?
Several countries decided to adopt a herd immunity strategy; At the forefront are Britain and Sweden, but with the number of deaths in both countries worsening as a result of this strategy; He forced them to retract its approval and immediately begin urgent, comprehensive, and violent quarantine measures. Despite Britain’s suffering from following the “herd immunity” policy and its late retreat from following it after the widespread criticism the government was subjected to, Sweden surprised the world by announcing the adoption of this policy, which aims to let the disease spread in the country in order to give the people collective immunity. The results were shocking. Infection and death rates increased daily in Sweden at a frightening pace, until the number of infections reached more than 12,000, and deaths exceeded 1,203 people, which is a much higher rate than neighboring Finland, Denmark, and Norway, due to their adoption of strict preventive measures and procedures. Unlike its neighbors and most of Europe, Sweden did not impose lockdown orders or bans, but rather called on citizens to be responsible and follow social distancing guidelines in addition to taking normal measures such as banning gatherings of more than 50 people, and stopping visits to nursing homes. In turn, Swedish scientists criticized the country’s public health agency and called on the government to reconsider and take “quick and radical measures”, in an article published in the newspaper “Dagens Nyheter”, which stated that “Sweden records ten times more deaths compared to neighboring Finland,” stressing the need to take the strict measures and measures taken by the Finnish authorities. The final blow to herd immunity came in Britain, at the beginning of this April, when British Prime Minister Boris Johnson was detained in intensive care after testing positive for the virus. Britain finally announced the victory of the virus over that strategy, declaring a state of general alert, hoping that it was not too late.
