Even vaccinated people with mild breakthrough infections can experience Long Covid -- debilitating, lingering symptoms that affect the heart, brain, lungs and other parts of the body, according to a study of over 13 million people in the US.
The research, published on Wednesday in the journal Nature Medicine, also shows that vaccination against Covid-19 reduced the risk of death by 34 per cent and the risk of getting long Covid by 15 per cent, compared with unvaccinated patients.
However, vaccines were shown to be most effective in preventing some of the worrisome manifestations of long Covid -- lung and blood-clotting disorders -- which declined about 49 per cent and 56 per cent, respectively, among those who were vaccinated.
"Vaccinations reduce the risk of hospitalisation and dying from Covid-19. But vaccines seem to only provide modest protection against long Covid," said first author Ziyad Al-Aly, a clinical epidemiologist at Washington University.
"People recovering from breakthrough Covid-19 infection should continue to monitor their health and see a health-care provider if lingering symptoms make it difficult to carry out daily activities," Al-Aly said in a statement.
The researchers classified patients as fully vaccinated if they had received two doses of the Moderna or Pfizer-BioNTech vaccines or one dose of the Johnson & Johnson/Janssen vaccine.
At the time the study was conducted, the database used for the research did not include information about whether patients had received boosters, the researchers said.
"Now that we understand that Covid-19 can have lingering health consequences even among the vaccinated, we need to move towards developing mitigation strategies that can be implemented for the longer term since it does not appear that COVID-19 is going away any time soon," said Al-Aly.
"We need to urgently develop and deploy additional layers of protection that could be sustainably implemented to reduce the risk of long COVID," he added. -- PTI