London: Antibodies formed in the body after getting infected with coronavirus will last in the body for at least nine months. A study by the University of Padua in Italy and Imperial College London in the UK assessed an entire Italian town to reach the conclusion.
Scientists tested over 85% of the 3,000 residents of Vo' in February and March 2020 and found that antibody levels were still high after nine months of infection. Findings show that 98.8% of people infected then showed detectable levels of antibodies in November.
There were no differences in case antibodies between people who had symptoms and those who were asymptotic.
Lead author IlariaDorigatti said that they found no evidence that antibody levels between symptomatic and asymptomatic infections differ significantly. It suggests that the strength of the immune response does not depend on the symptoms and the severity of the infection.
The team also found that some people experienced an increase in antibody levels. It could be due to re-infection which provide a boost to the immune system.
The study has found that the majority of infections generate no further infections, and only a minority of the infections cause a large number of infections. It confirms that in the absence of case isolation and short lockdowns, manual contact tracing alone would not have been enough to suppress the outbreak.
However, the level of antibodies varied depending on the tests used. "Tests that detect different types of antibodies which respond to different parts of the virus," said the author. The team thinks caution is needed when infection levels in a population are compared, various factors need to be cautiously considered in the estimation.
Professor Enrico Lavezzo, from the University of Padua, said that they found antibodies to be less abundant after nine months of the outbreak. The research team intends to continue to monitor antibody persistence for a longer period.
They also found a probability of about one in four that a person infected with SARS-CoV-2 passes the infection to a family member and that most transmission (79%) is caused by 20% of infections
The results are published in the journal Nature Communications.