Arushi Bidhuri
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Written By: Arushi Bidhuri | Updated : July 18, 2022 6:16 PM IST
Omicron virus.(IANS Infographics)
A lot of people have been vaccinated against the coronavirus with more variants emerging in the world. With variants moving freely, the COVID cases may increase again. As subvariants increase in the world, many people who have been vaccinated against COVID are afraid of reinfection. Turns out, new subvariants may be susceptible to reinfection sooner rather than later.
Health experts said that the protective window of past infection has been shortened from 12 weeks to 28 days. The governments of New South Wales, Western Australia, and the Australian Capital Territory all announced this week that those who have previously taken Covid-19 must retest after 28 days if they exhibit symptoms. They will be handled as new cases if the test is positive.
Reinfection is on the rise and refers to testing positive for SARS-CoV-2, the virus that causes Covid, after having recovered from an earlier infection. In the pre-Omicron period, reinfection accounted for 1 per cent of all cases in England, but in recent weeks, it accounted for more than 25 per cent of daily cases there and 18 per cent in New York City.
Although we lack comparable data for Australia, given the introduction of the BA.4 and BA.5 Omicron subvariants there, the situation will probably be similar. These can more easily spread and, in people who have already been vaccinated or infected, resulting in breakthrough infections.
The virus itself, how is the immune response of a person to prior COVID infection, their vaccination status and personal safety measures are the four main aspects that help us understand our risk of reinfection on an individual level. While the first two things are out of our control, you can work on the other two to see a difference.
While vaccination is your best defence against coronavirus, some variants can escape antibodies produced post-vaccination. Omicron strains have developed ways to avoid neutralisation by vaccine antibodies, so they can still infect persons who have received vaccinations.
A study published in The New England Journal of Medicine found that antibody levels against all Omicron subvariants reduce after the second dose of an mRNA vaccination. In other words, the vaccination loses its effectiveness faster against the subvariants of the virus than it does against the original strain. Two weeks after participants received a booster shot, antibody levels across all variants increased once more, however, BA.4 and BA.5 demonstrated the smallest incremental gains.
