The immunity that is generated against COVID-19 , whether mediated by vaccines or after managing to overcome the natural infection, continues to raise many unknowns. The most important ones focus on its duration and strength. The short period of relationship of SARS-CoV-2 with humans, means that the duration of immune memory and protective immunity after COVID-19 and in response to COVID-19 vaccines is still unknown . These topics will be a priority for scientific knowledge and control of the pandemic in the coming years.
A study published in the journal Cell Reports Medicine maintains that the natural immunity that is achieved after overcoming the natural infection by SARS-CoV-2 could be robust. 254 people were evaluated for up to eight months after overcoming COVID-19 and found to have long-lasting, broad-phase immune responses . Even in those patients who had had the disease mildly.
Scientific evidence shows that other diseases can confer long-lasting natural immunity. Infection with the chickenpox virus often provides people with natural immunity for life. A degree of protection that, to be achieved by vaccination, would require two injections administered several times apart.
«I don’t think anyone has collected enough data to say that a person who has overcome COVID-19 does not need to be vaccinated,» explains Ruth Karron , a pediatrician and professor at the Johns Hopkins School of Public Health , in National Geographic . «I would advise anyone who has not been vaccinated to get vaccinated as soon as possible, » adds Allison Greaney , a researcher at the Fred Hutchinson Cancer Research Center.
Within four weeks of infection, 90-99% of people infected with SARS-CoV-2 develop neutralizing antibodies (NAb). The strength and duration of the immune response are not fully understood and science has no data to suggest that immunity can vary in response to factors such as age of patients or severity with which coursed disease , collects the World Health Organization Health (WHO) in one of its documents .
Available information suggests that, in most people, immune responses remain robust and protective against reinfection for a period ranging from six to eight months after infection.
Experts point out that, despite results such as those presented, with vaccination most people are guaranteed to generate a strong immune response . Multiple studies have shown that even a single dose of mRNA vaccines increases antibody levels in recovered patients offering the same degree of response as those who have not fought the infection and have completed the vaccination regimen.
VACCINATION IN SPAIN
People with a history of symptomatic or asymptomatic infection by SARS-CoV-2, regardless of the date of confirmation, will be vaccinated according to age and time of infection , explains the Ministry of Health through the latest update of the National Strategy of Vaccination against COVID-19 .
“A person with a history of infection is considered to be one who has a positive test for active infection –PDIA- with a date prior to vaccination or a positive result of IgG by high-performance serology (ELISA or CLIA), regardless of the protein detected. Vaccines with a two-dose regimen (Comirnaty, Vaxzevria and Moderna vaccine) will preferably be used , taking into account the indication according to age ”. In this way, we find the following groups:
- People 65 years of age or younger with a diagnosis of SARS-CoV-2 infection before receiving the first dose: only one dose will be administered preferably from six months after the onset of symptoms or diagnosis of infection. If it is administered before these six months have elapsed, the dose will be considered valid and it will not be necessary to administer more doses.
- People 65 years of age or younger with a diagnosis of SARS-CoV-2 infection after receiving the first dose: A second dose will be administered six months after the onset of symptoms or diagnosis of infection.
- People over 65 years of age with a diagnosis of SARS-CoV-2 infection before receiving the first dose. A two-dose regimen will be administered when they are fully recovered and the isolation period is over. Do not wait six months after infection for the administration of the first dose.
- People over 65 years of age with a diagnosis of SARS-CoV-2 infection after receiving the first dose. The regimen will be completed with a second dose when they are fully recovered and the isolation period has ended, ensuring the recommended interval between doses. Do not wait six months after infection for the administration of the second dose.