Symptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Reinfection of a Healthcare Worker in a Belgian Nosocomial Outbreak Despite Primary Neutralizing Antibody Response

Abstract

Background It is currently unclear whether SARS-CoV-2 reinfection will remain a rare event, only occurring in individuals who fail to mount an effective immune response, or whether it will occur more frequently when humoral immunity wanes following primary infection. Methods A case of reinfection was observed in a Belgian nosocomial outbreak involving 3 patients and 2 health care workers. To distinguish reinfection from persistent infection and detect potential transmission clusters, whole genome sequencing was performed on nasopharyngeal swabs of all individuals including the reinfection case’s first episode. IgA, IgM, and IgG and neutralizing antibody responses were quantified in serum of all individuals, and viral infectiousness was measured in the swabs of the reinfection case. Results Reinfection was confirmed in a young, immunocompetent health care worker as viral genomes derived from the first and second episode belonged to different SARS-CoV-2 clades. The symptomatic reinfection occurred after an interval of 185 days, despite the development of an effective humoral immune response following symptomatic primary infection. The second episode, however, was milder and characterized by a fast rise in serum IgG and neutralizing antibodies. Although contact tracing and virus culture remained inconclusive, the health care worker formed a transmission cluster with 3 patients and showed evidence of virus replication but not of neutralizing antibodies in her nasopharyngeal swabs. Conclusion If this case is representative of most Covid-19 patients, long-lived protective immunity against SARS-CoV-2 after primary infection might not be likely.

Impact of Prior Infection on Protection and Transmission of SARS-CoV-2 in Golden Hamsters

“…However, it was not sterizing immunity, and the virus still moderately replicated in nasal turbinates of prior infected hamsters, indicating that prior infected hamsters can be artificially re-infected after a short recovery period, even with a high level of neutralization antibodies. The conclusion is consistent with recent reports showing that recovered COVID-19 patients were re-infected in the presence of neutralizing antibodies 24,25 . A large study of a recovered cohort of 175 COVID-19 patients revealed that 6% of COVID-19 patients did not show any antibody response at all, and about 30% COVID-19 patients showed very low neutralizing antibodies 26 .…”

Symptomatic SARS-CoV-2 Reinfection in a Healthy Healthcare Worker in Italy Confirmed by Whole-Genome Sequencing

“…The patient described here showed mild COVID-19 symptoms in both episodes. This is in accordance with cases reported from Hong Kong [ 18 ], Belgium [ 21 ], and the Netherlands [ 19 ] but in contrast with cases from Ecuador [ 20 ] and the UK [ 11 ], where patients presented with increased symptom severity in the second infection.…”

“…Second, the virus identified in the second infection did not harbor any known spike mutation that could have enabled escape from immunity induced by the primary infection. Moreover, approximately 9 months elapsed between the two COVID-19 episodes, which is much longer than the 185 days between infections reported by Selhorst et al for a Belgian HCW [ 21 ].…”

“…Due to this waning immunity, patients with mild COVID-19 disease are considered more susceptible to potential reinfections [ 17 ]. Several SARS-CoV-2 reinfections have been documented recently, including in healthcare workers (HCW) and inpatients with no history of clinically significant medical conditions [ 11 , 18 , 19 , 20 , 21 ]. The results of a survey conducted in the EU/EAA countries by the European Centre for Disease Prevention and Control (ECDC) at the end of January 2021, showed that 1.887 suspected cases of reinfection were reported in 2020 and 691 cases were under investigation in 2021 [ 22 ].…”

The future of masking

“…There is one report of COVID-19 reinfection in an otherwise healthy adult 6 months after the initial infection despite production of neutralizing antibodies after the first infection. 1 This individual apparently spread COVID-19 while reinfected, likely reflecting viral replication in the nares in the absence of neutralizing antibodies at that site (ie, lack of mucosal immunity). Widespread vaccination will inevitably reduce the COVID-19 reproductive number, thereby changing the transmission dynamics in many parts of the world.…”