Spain sees more Covid reinfections in last fortnight than rest of pandemic

A health worker collects a swab sample for a COVID-19 test from a woman.
A health worker collects a swab sample for a COVID-19 test. Infections in Spain have hit record highs in the last few weeks, driven by the contagious Omicron variant. Pau BARRENA / AFP
The Omicron coronavirus variant caused more reinfections in the last fortnight than that seen during the rest of the pandemic, data from Spanish researchers showed.

In the last two weeks, 20,890 infections were reported, according to the latest data from Spain’s state-backed Carlos III Health Institute (ISCIII). The data includes confirmed and suspected repeat infections.

This is higher than the 17,140 cases of repeat infection registered from the start of the pandemic to December 22nd.

The reinfections were due to the highly contagious Omicron variant, immunology professor Alfredo Corell told Spanish news site NIUS.

“Prior to this variant, reinfections were anecdotal at the global level. They were people who had lost their protection or were immunosuppressed. Omicron has changed this paradigm. We cannot say that there are no reinfections now – there are many,” he explained. 

Up until mid-November, there were fewer than one thousand reinfections a week, but that all changed in the last weeks of December, with numbers climbing to 2,451 and 7,817.

By then, Omicron was already present in 42.9 percent of the sequenced samples, according to the latest weekly data.

And the latest 14-day infection rate stood at 2,723 cases per 100,000 people, according to data from the Ministry of Health published on Friday.
“Although the possibility of reinfection is small – one in 100, if millions are infected, there will be tens of thousands of reinfections”, said José Antonio López Guerrero, director of the Neurovirology group and professor of microbiology at the Autonomous University of Madrid, speaking to NIUS.

The findings reinforce a December report from the UK’s Imperial College, which said that people were over five times more likely to get reinfected with Omicron than with Delta.  

Fortunately, reinfections are “rarely serious,” according to Julian Olalla, doctor and spokesperson for the Spanish Society of Infectious Diseases and Clinical Microbiology, adding there were currently no hospitalisations for cases of repeat infection.

“I haven’t seen any for a long time,” he added.

The most likely reason for the higher number of reinfections with Omicron is the more-than-40 mutations that the variant has in its spike protein, Corell said, explaining that this made it easier for the virus to evade the body’s antibodies.

But the body also has cellular immunity, which resists mutations better. Although this type of immunity won’t stop people becoming reinfected as it takes a few days to become active, it does prevent most serious disease, he explained.


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