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Last reviewed
July 20, 2022

Immunity Research

According to the U.S. CDC, immunity to disease results when antibodies are developed in a person's system to that particular disease. Immunity can be either active or passive.

Active immunity occurs when the immune system produces antibodies to the disease. Antibodies can be made in two ways: when an individual is exposed to the disease resulting in natural immunity, or when the individual is vaccinated, typically with a killed or weakened form of the disease, resulting in vaccine-induced immunity.

Passive immunity is through antibody-containing blood products such as immune globulin, which may be given when immediate protection from a specific disease is needed. The significant advantage of passive immunity: protection is immediate, whereas active immunity takes time (usually several weeks) to develop.

Children Innate Immunity

Childhood vaccine-mediated cross-cellular immunity and immunomodulation might protect against the infections of COVID-19, reported a study published in 2020. And the immunological mechanisms that lead to a lower susceptibility or severity in pediatric patients are not entirely clear. For example, milder symptomatology could be attributed to innate immunity or previous coronavirus infections, while it is not yet fully understood how the differential expression of ACE2 in children could contribute to milder disease.

Hybrid Immunity

An article published by Science on June 25, 2021, concluded by stating, 'Combining two different kinds of vaccines in heterologous prime-boost regimen can elicit substantially stronger immune responses than either modality alone. Hybrid immunity to SARS-CoV-2 appears to be impressively potent. The synergy is primarily observed for the antibody response more than the T cell response after vaccination, although the enhanced antibody response depends on memory T cells. This discordance needs to be better understood.'

Immunity Testing

Antibody or serology tests detect antibodies in the serum within days to weeks following infection. An antibody test will show whether or not you have developed antibodies to COVID-19 after exposure or vaccination. According to the U.S. CDC, antibody testing is not currently recommended to determine if you are immune to COVID-19. Antibody testing should also not be used to decide if someone needs to be vaccinated, says the CDC.

Herd Immunity

Another debated concept is 'Herd Immunity,' which is the indirect protection from a disease that occurs when a large percentage of a population is protected with antibodies to that particular disease. Herd immunity occurs when a large portion of a community (the herd) becomes immune to a disease, making the spread of disease from person to person unlikely, says the Mayo Clinic. As of February 2022, more than 25 studies have reviewed neutralizing antibodies, and memory B and T cells, that have shown synergy (beyond additivity) of the immune response when a person has both forms of immunity. 

SARS-CoV-2 Coronavirus Immunity

Most people infected with the SARS-CoV-2 betacoronavirus and its mutating variants develop an immune response after infection. And COVID-19 vaccines deliver various degrees of immunity against the virus variants.

On January 28, 2022, the U.S. CDC acknowledged after a SARS-CoV-2 infection, so-called "natural immunity" is verified. Natalie J. Thornburg, Ph.D., Lead respiratory virus immunology, U.S. CDC, presented 'Adaptive immunity and SARS-CoV-2' to the Advisory Committee on Immunization Practices meeting on September 22, 2021. The CDC stated data are presently insufficient to determine an antibody titer threshold that indicates when an individual is protected from infection. The immunity provided by vaccine and prior infection is both high but not complete.

Coronavirus Immunity Studies In 2022

July 15, 2022 - PNAS published a Research Article: The durability of natural infection and vaccine-induced immunity against future infection by SARS-CoV-2. Peak antibody levels elicited by messenger RNA (mRNA) vaccines mRNA-1273 and BNT1262b2 exceeded that of natural infection and are expected to typically yield more durable protection against breakthrough infections (median 29.6 mo; 5 to 95% quantiles 10.9 mo to 7.9 y) than natural infection (median 21.5 mo; 5 to 95% quantiles 3.5 mo to 7.1 y). Relative to mRNA-1273 and BNT1262b2, viral vector vaccines ChAdOx1 and Ad26.COV2.S exhibit similar peak anti-S IgG antibody responses to that from natural infection and are projected to yield lower, shorter-term protection against breakthrough infection (median 22.4 mo and 5 to 95% quantiles 4.3 mo to 7.2 y; and median 20.5 mo and 5 to 95% quantiles 2.6 mo to 7.0 y; respectively).

July 7, 2022 - The NEJM published an ORIGINAL ARTICLE: Effects of Previous Infection and Vaccination on Symptomatic Omicron Infections. Even though the five forms of immunity investigated showed large differences in protection against symptomatic infection that ranged from 0 to 80%, they all showed strong protection against Covid-19–related hospitalization and death, at the effectiveness of more than 70%. This suggests that any form of previous immunity, whether induced by previous infection or vaccination, is associated with strong and durable protection against Covid-19–related hospitalization and death. 

June 15, 2022 - The Peer-reviewed journal NEJM published Orginal Research that concluded: Even though the five forms of immunity investigated showed large differences in protection against symptomatic infection that ranged from 0 to 80%, they all showed strong protection against Covid-19–related hospitalization and death, at the effectiveness of more than 70%. This suggests that any form of previous immunity, whether induced by previous infection or vaccination, is associated with strong and durable protection against Covid-19–related hospitalization and death. 

June 13, 2022 - GAVI published: Hybrid immunity: a combination of vaccination and prior infection probably offers the best protection against COVID.

June 9, 2022 - The NEJM published an Original Article - Protection and Waning of Natural and Hybrid Immunity to SARS-CoV-2. Among persons who had been previously infected with SARS-CoV-2 (regardless of whether they had received any dose of vaccine or whether they had received one dose before or after infection), protection against reinfection decreased as the time increased since the last immunity-conferring event; however, this protection was higher than that conferred after the same time had elapsed since receipt of a second dose of the vaccine among previously uninfected persons. A single dose of vaccine after infection reinforced protection against reinfection.

June 5, 2022 - The peer-review journal The Lancet published a study on the effectiveness of COVID-19 vaccines and the waning of immunity with time. The study showed that immune function among vaccinated individuals 8 months after the administration of two doses of a COVID-19 vaccine was lower than that among the unvaccinated individuals. 

April 29, 2022 - Africa Health Research Institute reported: Omicron sub-lineages BA.4/BA.5 escape BA.1 infection elicited neutralizing immunity.

April 28, 2022 - The journal Nature published: Disentangling the relative importance of T cell responses in COVID-19: leading actors or supporting cast?

April 26, 2022 - Study: Innate immune suppression by SARS-CoV-2 mRNA vaccinations: The role of G-quadruplexes, exosomes, and MicroRNAs. Suppression of type I interferon responses results in impaired innate immunity.

April 20, 2022 - “We found that, before the emergence of the omicron variant, natural immunity provided a similar degree of protection against COVID-19 infection as mRNA vaccination,” said Ari Robicsek, M.D., Providence’s chief medical analytics officer and senior author of a recent study. “That said, vaccination is a considerably safer way to acquire that immunity.”

April 15, 2022 - Innate immune suppression by SARS-CoV-2 mRNA vaccinations: The role of G-quadruplexes, exosomes, and MicroRNAs: mRNA vaccines promote sustained synthesis of the SARS-CoV-2 spike protein; The spike protein is neurotoxic, and it impairs DNA repair mechanisms; Suppression of type I interferon responses results in impaired innate immunity; The mRNA vaccines potentially cause increased risk to infectious diseases and cancer; Codon optimization results in G-rich mRNA that has unpredictable, complex effects.

March 24, 2022 - Science Immunology published: Understanding T-cell responses to COVID-19 is essential for informing public health strategies.

March 22, 2022 - JCI published a study: Binding and neutralizing antibody responses to SARS-CoV-2 in young children exceed those in adults. Children aged 0-4 years had only 2-fold higher neutralizing Ab than adults, resulting in higher binding to neutralizing (B/N) Ab ratios than adults (2.36 vs. 0.35 for ID50, P=0.0002). CONCLUSION - These findings suggest that young children mount robust antibody responses to SARS-CoV-2 following community infections.

March 18, 2022 - Durability of SARS-CoV-2 Antibodies From Natural Infection in Children and Adolescents - The data reported here show that the majority of children followed for > six months and who had three successive antibody test results available for analysis retained SARS-CoV-2 antibodies over the entire time period regardless of age, sex, COVID-19 symptom status and severity, and body mass index. These results suggest that infection-induced antibodies persist and thus may provide some protection against future infection for at least half a year.

March 12, 2022 - Clinical Infectious Diseases published a study: Antibody-mediated Immunogenicity against SARS-CoV-2 following priming, boosting, and hybrid immunity: insights from 11 months of follow-up of a healthcare worker cohort in Israel, December 2020-October 202. Conclusions - Immunity waned in all age groups and previously infected individuals, reversed by boosting. IgG titers decrease, and reinfections in individuals with hybrid immunity (infection+vaccination) suggest they may also require further doses. Our study also highlights the difficulty in determining protective IgG levels.

March 9, 2022 - The JAMA Network reported: What proportion of children with mild SARS-CoV-2 infection undergo seroconversion compared with adults? Study Findings: In this cohort study of 57 children and 51 adults, the proportion of children with seroconversion to SARS-CoV-2 was half that found in adults despite a similar viral load.

February 15, 2022 - An extensive, Original Research Retrospective Cohort Study - The Incidence of SARS-CoV-2 Reinfection in Persons With Naturally Acquired Immunity With and Without Subsequent Receipt of a Single Dose of BNT162b2 Vaccine - concluded that persons who were previously infected and received a single dose of the vaccine had an 82% decreased rate of breakthrough infection compared with those who were previously infected but unvaccinated. The reduced risk was significant for symptomatic disease as well.

February 3, 2022 - The peer-reviewed JAMA Network published a Research Letter - Prevalence and Durability of SARS-CoV-2 Antibodies Among Unvaccinated US Adults by History of COVID-19. In this cross-sectional study of unvaccinated US adults, antibodies were detected in 99% of individuals who reported a positive COVID-19 test result, in 55% who believed they had COVID-19 but were never tested, and in 11% who thought they had never had COVID-19 infection. In addition, anti-RBD levels were observed after a positive COVID-19 test result up to 20 months, extending the previous 6-month durability data. Although evidence of natural immunity in unvaccinated healthy US adults up to 20 months after confirmed COVID-19 infection is encouraging, it is unclear how these antibody levels correlate with protection against future SARS-CoV-2 infections, particularly with emerging variants. 

February 1, 2022 - The journal Nature published a preprint study that found 'never-COVID' status in about 50% of participants in a limited human-challenge study.

December 1, 2020 - Viral nucleoprotein antibodies activate TRIM21 and induce T cell immunity. These results reveal a new mechanism of immune synergy between antibodies and T cells and highlight N as an important vaccine target.

Note: This page's content is aggregated from the US CDC, WHO, EMA, pharmaceutical manufacturers, university studies, the Precision Vaccinations news network, and other trusted sources. This content is reviewed by healthcare professionals, such as Dr. Robert Carlson.