Antibodies in the nose were found only in those who had been recently infected and were especially short-lived against the Omicron form compared to earlier variants, according to the researchers.

Reinfection with COVID-19

These new findings, ed eBioMedicineIt may help explain why individuals who have recovered from COVID-19 remain susceptible to reinfection, particularly with Omicron and its subvariants.


The study also found that while immunization was quite successful in generating and boosting antibodies in the blood, preventing severe disease, it had little effect on nasal IgA levels.

The first author of the study, Dr. from the National Heart and Lung Institute of Imperial College London. Felicity Liew, “Prior to our study, it was not clear how long these important nasal antibodies last. Our study found persistent immune responses after infection and vaccination, but these essential nasal antibodies were shorter-lived than those in the blood. Although blood antibodies help protect against disease, nasal antibodies can help protect against infection.” can be completely prevented. may be an important factor behind re-infections with SARS-CoV-2. virus and its new variants.”

Nasal Antibodies and COVID-19 Reinfections

The researchers stress that more research is needed on antibodies in the nose and reinfections to confirm their findings.

The research is led by Imperial College London and the University of Liverpool. Before the introduction of the Omicron strain and vaccine, about 450 people hospitalized with COVID-19 were looked at between February 2020 and March 2021.

COVID-19 Vaccines Raise Blood Antibody Levels

The study also found that while current vaccines are successful in increasing blood antibody levels that can prevent serious illness and death, they do not significantly increase nasal IgA levels.

Can Nasal COVID-19 Vaccines Improve Nasal Antibody Levels?

Researchers are advocating for the next generation of immunization to include nasal spray or inhaled vaccines that more effectively target these antibodies. They believe that vaccines that can boost these antibodies can help minimize infections and prevent transmission.

Professor Peter Openshaw, from the National Heart and Lung Institute, Imperial College London, lead author of the study, said: “Our results highlight the need for nasal spray vaccines that can boost these local antibodies in the nose and lungs. Such vaccines could prevent people from becoming infected with SARS-CoV-2 and prevent human-to-human transmission of the virus. It can help us better control the pandemic and stop new variants emerging.”

He continues: “Our existing vaccines are designed to reduce severe disease and death and are dramatically effective in doing so. It is also important now to develop nasal spray vaccines that can provide better protection against infection. Existing vaccines mean that fewer people become seriously ill, but it would be better if we could prevent their infection and transmission of the virus.”

Recovery of Nasal Antibodies Compared with Blood Antibodies

The researchers looked at the subjects’ antibodies to see how long the antibodies in the nose survived compared to blood antibodies. They also looked at how repeated COVID-19 vaccines affect antibodies in the nose and blood.

Samples were collected when participants entered the hospital, as well as six months and one year later. Because most participants were vaccinated during the trial, several samples were collected before and after vaccination.

They evaluated how effectively the antibodies neutralized the original SARS-CoV-2 virus, as well as the Delta and Omicron versions, to determine how effective the antibodies were after infection or vaccination.

The study involved 446 people who attended hospitals in the early stages of the pandemic, with 141 providing samples at the start of the trial, as well as six and twelve months later. The researchers used modeling to predict how average antibody responses changed over time for patients who received only one sample during the 12-month trial period.

Of those who confirmed vaccination, 95% (307) (323) received their first vaccine during study follow-up. Whole nasal and blood antibodies increased, whereas the change in primary defensive nasal antibodies (IgA) was small and transient. The researchers found that an individual’s sex, disease severity and age did not affect how long their nasal immunity lasted, although they cautioned that their study included only those with severe disease who needed hospitalization.

They also found that the participants’ blood antibodies continued to block the original SARS-CoV-2 virus, as well as the Delta and Omicron variants, one year after infection, but a booster immunization was required to maintain this immunity.

The lead author of the study, Dr. Dr. Lance Turtle said: “Our study shows that this first-line defense immunity is distinct from other immune responses. , and although it is boosted by vaccination and infection, it only lasts about nine months. However, booster vaccines can increase it slightly and otherwise have a significant effect on other areas of immunity, very effectively protecting against severe disease and death, so stay tuned . very important.”

The researchers emphasize that their study screened participants for re-infection, but that this was impossible because the trial was conducted during periods of national restrictions and lockdowns when cases of COVID-19 were low and individuals did not mix. They found only two cases of reinfection in their initial study, suggesting that the underlying patterns observed were correct.

Source: Medium

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