Jiao Liu, Jun Guo, Qianghong Xu, and Guolong Cai are listed as co-first authors.
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Although most patients with COVID-19 in China have been cured and discharged, we noticed a small proportion of these patients had re-positive RT-PCR test during the follow-up period [1]. The causes of this re-infection remain unclear. In common COVID-19 cases [2], both the IgM and IgG antibodies significantly increased within a short period. However, in a case series report [3], the IgG was relatively low in re-infected COVID-19 cases. Thus, we investigated the IgG status in recovered patients during the follow-up period.
This retrospective study was performed in Wuhan JiangBei Hospital, China. COVID-19 infection was confirmed by the RT-PCR test. The IgM and IgG antibodies were detected using colloidal immunization methods. Only cured patients were included in this analysis. Patient consent was waived due to the retrospective nature. The ethics committee of Wuhan JiangBei Hospital approved this study.
Anzeige
During follow-up, only simple tests were performed, such as blood routine examination, antibody test, and chest computed tomography (CT). For accuracy, missing data were not imputed.
Continuous variables were presented as mean ± standard deviation, and Student’s t test was used unless indicated. Categorical data were compared using the chi-square test. p < 0.05 was considered statistically significant. All statistical analyses were performed using STATA 14.0.
We studied 484 patients with positive IgG, the minimum period from onset to IgG detection was 10 days, and the maximum period was 100 days (Fig. 1). Meanwhile, 18% of these patients had negative IgG results, and this was confirmed by more than two IgG tests in 37 patients. The mean duration from onset to IgG test was close between positive and negative IgG groups (50.5 ± 14.8 vs. 43.3 ± 15.0, days).
Fig. 1
Maximum period from disease onset to IgG detection in the negative and positive IgG groups
×
Further, compared to the negative IgG group, both the lymphocyte (1.3 ± 0.0 vs. 1.6 ± 0.1, p = 0.001) and neutrophil counts (3.5 ± 1.6 vs. 5.0 ± 3.0, p < 0.001) were lower in the positive group. Besides, the percent of abnormal CT findings at follow-up was higher in the positive IgG group (259/372 vs. 22/64, p < 0.001) (Table 1).
Table 1
Comparisons between patients with positive and negative IgG antibody
Variables
Positive IgG (n = 397)
Negative IgG (n = 87)
Negative IgG (≥ 2 tests) (n = 37)
p
Age (years)
51.2 ± 13.9
49.6 ± 17.2
51.8 ± 19.4
0.365
Gender (male, %)
190 (47.8)
43 (49.4)
13 (35.1)
0.791
White blood cell count on admission
5.3 ± 1.8
7.1 ± 3.1
6.9 ± 2.7
< 0.001
Lymphocyte count on admission
1.3 ± 0.0
1.6 ± 0.1
1.6 ± 0.7
0.001
Neutrophil count on admission
3.5 ± 1.6
5.0 ± 3.0
4.7 ± 2.5
< 0.001
White blood cell count at follow-up
6.3 ± 1.7
6.5 ± 1.8
6.2 ± 1.8
0.387
Lymphocyte count at follow-up
2.1 ± 0.6
2.1 ± 0.6
2.0 ± 0.7
0.738
Neutrophil count at follow-up
3.7 ± 1.4
3.9 ± 1.4
3.6 ± 1.3
0.296
Maximum duration of IgG test
50.5 ± 14.8
43.3 ± 15.0
50.6 ± 12.1
< 0.001
Maximum duration of IgG test*, median (min and max value)
51 (10–100)
42 (2–90)
50 (28–90)
< 0.001
Abnormal CT findings at follow-up# (which indicate residual infection)
259/372
22/64
10/32
< 0.001
All comparisons were made between positive IgG and negative IgG groups
IgG immunoglobulin G, CT computed tomography
*Presented as median (minimum and maximum value), compared using rank-sum test
#Any chest CT findings that suggested residual infection during follow-up were defined as abnormal
Anzeige
Re-infection with COVID-19 in recovered patients has been occasionally encountered in clinical practice. Weak evidence [3] indicated that the IgG level was low in these re-infected COVID-19 cases. As IgG plays a critical role in immune response, understanding IgG status in recovered patients is necessary for preventing re-infections. In the current study, we found that 18% of the recovered patients had negative IgG. The mechanism remains unclear. However, we also found that compared to the positive group, the lymphocyte on hospital admission was higher in the negative group. Evidence [4, 5] has indicated that lymphocyte count is an independent predictor for COVID-19 severity. Thus, we inferred that compared to patients with positive IgG, those with negative IgG might have relatively mild COVID-19 infection, and the slight impact on their immune system leads to the higher lymphocyte and negative IgG during the follow-up period. This hypothesis was also supported by the CT finding that the residual infection on chest CT disappears more quickly in patients with negative IgG. If this is the case, the risk of re-infection of COVID-19 in these patients should be carefully assessed in the later stage of epidemic prevention.
This study was limited by the qualitative IgG tests and short follow-up period. Further study should focus on the time-dependent change of the antibody level and the identification of those who are still at risk of re-infection in recovered patients.
Acknowledgements
Not applicable.
Ethics approval and consent to participate
Not applicable.
Consent for publication
Not applicable.
Competing interests
None.
Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Das Niveau der postpandemischen Fallzahlen für invasive Pneumokokken-Erkrankungen (IPD) ist aus Sicht des Referenz-Zentrums für Streptokokken in Aachen alarmierend [1]. Wie sich die monatlichen IPD-Fallzahlen bei Kindern und Jugendlichen von Juli 2015 bis März 2023 entwickelt haben, lesen Sie hier.
Auch nach dem 18. Lebensjahr kann eine HPV-Impfung sinnvoll und wichtig sein. Viele gesetzliche Krankenkassen übernehmen die Kosten auch zu einem späteren Zeitpunkt noch.
Seit mehr als 130 Jahren entwickelt und produziert MSD Impfstoffe für alle Altersgruppen. Hier finden Sie nützliche Informationen und Praxismaterialien rund um das Thema Impfen.
Nicht-medikamentöse Behandlungsmethoden wie die nicht-invasive Beatmung (NIV) können die Leistungsfähigkeit und Lebensqualität von COPD-Patienten erheblich verbessern und das Sterberisiko senken. Die NIV-Therapie zur Behandlung von fortgeschrittener COPD hat Eingang in die neuen S2k-Leitlinien zur COPD-Therapie gefunden.
Ärzte profitieren von digitaler Therapiebegleitung ihrer NIV-Patienten durch einen verlässlichen Partner, weil diese sich besser versorgt fühlen und die Therapie weniger häufig abbrechen. Das entlastet das Gesundheitssystem und schwer Erkrankte gewinnen Lebensqualität.
Nicht-invasive Beatmung ist für Menschen mit chronisch hyperkapnisch respiratorischer Insuffizienz eine bewährte Therapie. Eine Schweizer Studie untersuchte die Auswirkungen der Beatmung auf über 75-Jährige und belegt nun deren Wirksamkeit.
