A study in the states of California and New York revealed new data on Delta, which was rapidly the dominant variant in the US and many parts of the world before Omicron.
The experts concluded that innate immunity provides better protection against the Delta variant. According to the study, those who had previously contracted Covid-19 and produced natural antibodies were better protected against the Delta variant than those who did not get the disease but were vaccinated.
According to the study, those who were most protected against the Delta variant were both those who had the disease and were vaccinated; those who were least protected were neither infected nor vaccinated.
However, the Omicron variant, which currently accounts for 99.5 percent of cases in the USA, was not included in the study.
Still, the safest strategy against Covid-19 is vaccination, according to the Centers for Disease Control and Prevention (CDC) Disease and Loss of Death Weekly Report.
One of the study’s authors, CDC expert Dr. Ben Silk said, “The data in this report does not change our recommendation to get vaccinated. “We know that vaccines are still the safest way to protect ourselves against Covid-19.”
According to data collected by California and New York health officials between May and November, when the Delta variant predominates, the rate of re-infection of those previously infected with Covid-19 was lower than the rate of contracting the disease for those who were only vaccinated.
Silk said this differs from when the Alpha variant was dominant.
Silk noted that prior to the emergence of the Delta variant, Covid-19 vaccines provided more protection than the immunity developed by those who contracted the disease.
However, in the summer and fall of 2021, Delta became the dominant variant in the US. Having a previous infection during this period provided more protection against a new infection than vaccines.
Natural immunity has risks
However, according to the study, naturally; in other words, there are some important risks of gaining immunity by passing the disease. According to the study, by November 30, 2021, 130,781 California and New York residents died from Covid-19.
The study did not include information on the severity of the initial infection, nor did it take into account all diseases caused by previous infection. In addition, the study was completed before supplemental doses were started.
‘Vaccines provide the safest protection’
California Department of Public Health epidemic specialist Dr. Erica Pan said that the study shows that vaccines provide the safest protection against Covid-19, and additional protection to those who have previously contracted the disease.
Apart from this study, recent data on the highly contagious Omicron variant show that the booster dose provides significant additional protection against infections, hospitalization and death, Pan said.
Doctor Ben Silk also announced that the CDC is also working on the Omicron variant on the effect of vaccines, booster dose and previous infection, and that they will share data when possible.