PETALING JAYA: With varying findings coming out on the impact of Covid-19 reinfection, health experts warn it is instead best to take precautions to prevent getting ill again with the virus.
Universiti Kebangsaan Malaysia’s Health Economy and Public Health specialist Prof Dr Sharifa Ezat Wan Puteh said reinfection could happen as early as three weeks after the previous infection, pointing to medical literature that says a person can be infected up to four times.
“With a good immune system response, reinfection can be mild, but in certain cases, reinfection can happen even when you have yet to recover from the first infection. “That is, you are still recovering when you contract another infection.
“What happens in many cases of reinfection is that the immune system gets damaged, meaning your organs can get infected. Your lungs, heart and respiratory system can get infected again.
“Some patients can go on to develop long Covid. Most of these are new data, so we do not really know the risk, and so on,” she said, adding it would be best to take all precautionary measures to prevent reinfection.
Prof Dr Moy Foong Ming of Universiti Malaya’s Faculty of Medicine said studies have shown that reinfection cases were more likely to present mild illness compared to primary infection cases.
“Primary infection provides some protection against reinfection and reduces the risk of symptomatic infection and severe illness. Reinfection does not contribute to extra risk of hospitalisation, ICU, or death,” she said.
Citing a United Kingdom survey on self-reported long Covid after a coronavirus reinfection, Prof Moy said 4% of adults aged 16 years and over and 1% of children and young people aged between two and 15 years reported having long Covid in about 12 to 20 weeks after a first infection.
“Among those who did not report having long Covid after a first Covid-19 infection, 2.4% of adults and 0.6% of children and young people reported having long Covid following a second infection,” she said.
She added that based on the study and after taking into account factors such as vaccination status, adults infected with Covid-19 for the second time were nearly 30% less likely to report new-onset of long Covid, compared with those infected for the first time.
“However, there remains some risk of new-onset long Covid-19 after a second Covid-19 infection, with around one in 40 adults and one in 165 children and young people reporting long Covid symptoms 12 to 20 weeks after a second infection,” she said.
She said vaccines did offer protection against Covid-19 reinfection to a certain extent.
“The vaccines are made to prevent severe disease. The viruses are continuing to mutate and circulate, and some variants may get more infectious and evade our immunity,” she said.
“In addition, the vaccines are made for a specific strain, and as that strain changes, the vaccines have to be updated. Bivalent vaccines may provide better protection,” she said.
According to Nature journal, two large studies have suggested that reinfections tend to be less risky than the initial ones.
“In one study, researchers compared two groups of unvaccinated people in Qatar – around 6,000 who had been infected once and 1,300 who had been reinfected. The odds of severe, critical or fatal disease at reinfection were almost 90% lower than that for a primary infection,” the journal said.
The other study, which looked at 3.8 million first infections and 14,000 reinfection in England, found that people were 61% less likely to die in the month following a re-infection than in the same period after a first infection and 76% less likely to be admitted to an intensive care unit.
