Segal wrote that the vaccines only stimulate internal immunity but do nothing to address mucosal immunity. Internal immunity protects the inside of the body while mucosal immunity provides the first line of defense by protecting the nose and mouth, and by doing so also reduces spread to others.
He said that all COVID-19 vaccines "are largely ineffective at stimulating the secretion of a particular form of antibodies called Immunoglobulin A (IgA) into our noses that occurs after actual infection with a virus." Meanwhile, those who have contracted and recovered from the disease have both mucosal and internal immunity. They have what they call a natural immunity from the disease.
A recent study in Israel proved that natural immunity is better than getting vaccinated. The researchers found that vaccinated people were 13 times as likely to become infected and 27 times as likely to have symptomatic infections as people with natural immunity. (Related: COVID-19 natural immunity vs vaccine-induced immunity guide.)
An Emory University study published in the journal Cell Reports Medicine found that most people who have recovered from COVID-19 retain a broad and durable immunity to the disease, including some degree of protection against its variants.
Rafi Ahmed, the lead author of the paper, said that the findings disproved early reports during the pandemic that protective neutralizing antibodies did not last in COVID-19 patients.
"The study serves as a framework to define and predict long-lived immunity to SARS-CoV-2 after natural infection. We also saw indications in this phase that natural immunity could continue to persist," Ahmed said. SARS-CoV-2 is the virus that causes COVID-19.
After people recover from infection with a virus, the immune system retains a memory of it. Immune cells and proteins that circulate in the body can recognize and kill the pathogen if it's encountered again, protecting against disease and reducing illness severity.
The study involved 254 COVID-19 patients between 18 to 82 years old, who provided blood samples at various points for a period of over eight months beginning April last year. About 71 percent of the patients had mild disease, 24 percent experienced moderate illness and five percent had severe disease.
Ahmed and his team found that most of the patients who recovered mounted a strong and wide-ranging immune response to the virus for at least the 250-day duration of the study.
Long-term immune protection involves several components. Antibodies recognize foreign substances like viruses and neutralize them. Different types of T cells help recognize and kill pathogens. B cells make new antibodies when the body needs them.
All of these immune system components have been found in people who recovered from COVID-19. But the details of this immune response and how long it lasts after infection have been unclear. Scattered reports of reinfection with SARS-CoV-2 have raised concerns that the immune response to the virus might not be durable.
A study published on Jan. 6 in Science analyzed immune cells and antibodies from almost 200 people who had been exposed to SARS-CoV-2 and recovered.
Drs. Daniela Weiskopf, Alessandro Sette and Shane Crotty from the La Jolla Institute for Immunology led the study. It was funded in part by the National Institute of Allergy and Infectious Diseases (NIAID) and the National Cancer Institute (NCI).
Time since infection ranged from six days after symptom onset to eight months later. More than 40 participants had been recovered for more than six months before the study began. About 50 people provided blood samples at more than one time after infection.
The researchers found durable immune responses in the majority of people studied.
Antibodies against the spike protein of SARS-CoV-2 were found in 98 percent of participants one month after symptom onset. As seen in previous studies, the number of antibodies ranged widely between individuals. But their levels remained fairly stable over time, declining only modestly at six to eight months after infection.
Some experts are now recommending that the virus be allowed to circulate throughout the population, with precautions taken for vulnerable individuals.
"We don't have anything that will stop transmission, so I think we are in a situation where herd immunity is not a possibility and I suspect the virus will throw up a new variant that is even better at infecting vaccinated individuals," Andrew Pollard, director of the Oxford Vaccine Group, told a parliamentary panel last month.
Pollard argued that if mass testing was not stopped, "the UK could be in a situation of continually vaccinating the population." He said that only those with symptoms should be tested while others should go about their daily lives.
Iceland's state epidemiologist voiced similar sentiments.
"We really cannot do anything else but allow the virus to take its course in order for the population to achieve herd immunity," said Porolfur Gudnason, chief epidemiologist of Iceland's Directorate of Health. (Related: Study: 2 in 3 Indians have natural immunity against coronavirus, meaning "herd immunity" is already achieved.)
"We need to try to vaccinate and better protect those who are vulnerable but let us tolerate the infection. It is not a priority now to vaccinate everyone with the third dose."
Governments need to stop mass vaccination drives to get a shot at herd immunity.
In March, vaccine expert Dr. Geert Vanden Bossche said in an open letter that ongoing mass vaccination drives are "likely to further enhance adaptive immune escape as none of the current vaccines will prevent replication or transmission of viral variants."
Immune escape is a term used to describe when the host is no longer able to recognize and counter a pathogen such as a relevant variant or mutant of SARS-CoV-2.
"The more we use these vaccines for immunizing people in the midst of a pandemic, the more infectious the virus will become," Vanden Bossche wrote. "With increasing infectiousness comes an increased likelihood of viral resistance to the vaccines."
Under this scenario, manufacturers will be forced to refine or improve the vaccines, which will then increase the selection pressure.
Selection pressure is a term used to describe the process that helps an organism or pathogen to evolve in ways that make it better adapted to its changing environment. An antibiotic resistance, which is caused by overuse of antibiotic drugs, is a good example of selection pressure.
The virus will effectively outsmart the highly specific antigen-based vaccines that are being used and tweaked. Vanden Bossche said the "much more infectious" viral variants are already examples of immune escape from our innate immunity.
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