Study Validates Previous Findings That SARS-CoV-2 Reinfections Are Now Occurring At Shorter Intervals. Current CDC and ECDC Reinfection Definitions Are Obsolete!
A new study by researchers from Aix Marseille University- France and the Institut Hospitalo-Universitaire Méditerranée Infection-France has found that SARS-CoV-2 Reinfections involving the various Omicron variants and sub-lineages are occurring at shorter intervals between each infection.
The study team described 188 patients in France who were successively infected with different SARS-CoV-2 Omicron subvariants, including BA.1, BA.2, and BA.5. Time between 2 infections was <90 days for 50 (26.6%) patients and <60 days for 28 (14.9%) patients.
The study findings suggested that current definitions for SARS-CoV-2 reinfection require revision since the U.S. CDC guidelines uses 90 days while the ECDC uses 60 days as defining periods for re-infections.
The study findings were published in the peer reviewed journal: in Emerging Infectious Diseases. (A journal of the U.S. CDC)
The study finding validates a previous Danish study that found reinfections with the various Omicron variants and sub-lineages were occurring at a very short interval span of between 20 to 60 days!
In the Danish study, a total of 187 reinfection case were studied in detail and the Danish researchers identified 47 instances of BA.2 reinfections shortly after a BA.1 infection, mostly in young unvaccinated individuals with mild disease not resulting in hospitalization or death in periods spanning between 20 to 60 days!
Thailand Medical News
warns that with the new Omicron variants such as BA.2.75.2, BQ.1.1, BW.1, BU.1, BN.1, XBB, BR.2, BJ.1. BM.1.1.1 and CA.1, expect intervals between infections and reinfections to be even shorter ie anything from 10 to 16 days (They could also be a scenario of no intervals but rather co-infections taking place!) as these newer variants are totally evasive towards natural immunity from previous infections and also vaccine induced immunity and also evasive to all known monoclonal therapeutics!
The French study team observed early recurrence of coronavirus disease 2019 (COVID-19).
A total of ninety-six cases of early reinfections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were reported in Belgium between December 2021 and March 10, 2022, with a median interval of 47 days between two positive samples. Notably, five had primary infections with SARS-CoV-2 Omicron BA.1 and reinfection with BA.2 variant.
The same study team had in in earlier study reported a six-fold higher risk of reinfection with the Omicron variant than with other variants.
The current study described COVID-19 reinfection cases with different Omicron sub-variants after a primary infection with the BA.1 or BA.2 variant in Marseilles, France. Real-time reverse transcription polymerase chain reaction (RT-PCR) tests and next-generation sequencin
g (NGS) were performed using nasopharyngeal swab samples. Electronic medical files were accessed to obtain data on patients’ age and gender.
All the reinfected patients were identified utilizing a computerized alert system focusing on primary Omicron BA.1/BA.2 infections and reinfection with any Omicron sub-variant. Of nearly 28,000 positive samples from November 2021 to July 2022, 188 (0.7%) reinfection cases were identified. Among these, 181 patients had primary infection with SARS-CoV-2 Omicron BA.1 and reinfection with BA.2 (82 cases), BA.4 (14 cases), and BA.5 (85).
It was found that seven cases had primary infection with SARS-CoV-2 Omicron BA.2, followed by BA.4 reinfection in one patient and BA.5 reinfection in six patients.
Notably, three cases were reinfected twice; the first reinfection occurred with the BA.1 variant, and the second reinfection with the BA.5 variant. Most reinfected cases (69.7%) were females; the median age of patients was 32 years.
The study findings showed that the median duration between primary Omicron BA.1 infection and reinfection with BA.2 was 84 days, and 171 days for those with primary BA.1 infection and BA.5 reinfection.
However, the time between primary infection and reinfections was less than 30 days for six patients (3.2%), 30 to 44 days for four patients (2.1%), 45 to 49 days for 18 patients (9.6%), 60 to 70 days for 10 cases (5.3%), 75 to 89 days for 11 patients (5.8%), and more than 90 days for 139 patients (73.9%). Fifty patients (26.6%) had reinfection less than 90 days after primary infection.
The study findings showed that reinfections with SARS-CoV-2 Omicron sub-variants were frequently shorter than 90 days, a period used by the United States (US) Centers for Disease Control and Prevention (CDC) for reinfection definition. Further, reinfections occurred less than 60 days post-primary infection in some cases, shorter than the reinfection definition used by the European Centre for Disease Prevention and Control (ECDC).
It was noted that one of the study’s major limitations was the small number of reinfection cases. The study team could not rule out concurrent infections with different Omicron sub-variants in some patients.
These study findings suggest revising current definitions for reinfections regarding the duration between primary and secondary infections especially with the debut of various new Omicron variants and sub-lineages that are even more immune evasive.
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