Vaccines work well in the first months after vaccination and against those used to make them. However Lancet Microbe the study showed a reduced effectiveness of the vaccine against COVID-19 disease due to other tumors, such as Delta, which deteriorated over time.
The analysis was able to predict this decrease based on the analysis of antibody levels.
“Our previous studies showed that we can measure levels of neutralizing antibodies as a ‘proxy server’ for immune protection against COVID-19 infection. In this new analysis, we have tested this for variations of concern, including Delta, and found that differences between the viral sequences of the variants, “said the director. author Dr. Deborah Cromer, Kirby Institute, Sydney, UNSW.
The main effect of the study was that booster vaccines for COVID-19 were needed to maintain immune protection in the general population. Without the effects, protection against the symptoms of COVID can be reduced to less than 50% after six months, meaning that more people will be infected.
“Reassuringly, however, protection against serious illness and death is likely to remain high for the first year,” Dr. Cromer said.
“The optimal timing for the effects depends on the availability of booster vaccines and whether the goal is to reduce the overall number of cases or reduce the burden on the health care system.”
The model gives policy makers a clearer picture of how the level of protection against symptomatic diseases, serious illnesses and death is likely to change over time with different vaccines, new variants and over time.
In Australia, the TGA recently approved booster doses after six months, helping to maintain a high level of protection against all stages of the disease.
The analysis also found that booster vaccination within a year increases the level of immunity to a higher level than after a full primary vaccination schedule.
“This is excellent news, especially for people who have been six months since their first vaccination and are currently being offered a third dose of vaccination in Australia,” said Dr Cromer.
“Vaccines have had an incredible impact in controlling the current COVID-19 epidemic and will continue to provide very good protection. But boosters make this good protection even better. “