"One person was first infected in spring but now in autumn - the second time. It is a worker in risk group, so a medical or social service worker. The other person was first infected abroad, in spring, but now in Latvia," said Perevoščikovs.
According to him, in both cases, more than three months have passed between infections.
Re-infection with SARS-CoV-2 is extremely rare, with just dozens of cases currently registered around the world, Perevoščikovs acknowledged.
Cases of reinfection described in studies have occurred mainly three and more months since the first disease. "But there have been reports of recurrent illness 45 days after the first. Studies have shown that persistent immunity remained three to five months after the first infection with SARS-CoV-2, including after a lighter asymptomatic infection," Perevoščikovs said.
Current data show that a person who has already suffered COVID-19 (even in mild form or without symptoms) has a lower risk of re-infection for three months.
If contact with COVID-19 takes place more than three months after the first illness, the person should be considered to be at the same risk as any other person who had not previously been infected, the epidemiologist said.
Perevoščikovs also said that these cases are not paid too much attention.
"We have two cases, but there is no time to write a scientific article and make it known to the world. The subject has not been described at all yet," the epidemiologist said.
In fact, he thinks the number of cases of recurrent disease is higher, but every example needs to be studied in order to "get to the scientific publication".
The epidemiologist also warned that it was too early to draw any conclusions – not even a year has passed since the beginning of the pandemic. "And people who get sick in the spring are a very small percentage of the population. Therefore, today, even purely mathematically, there is a very small probability that one of the people who fell ill will now get ill again," said Perevoščikovs.
According to today's data on this issue, those who have already suffered COVID-19 should still use a mask, the epidemiologist said.