Mild COVID-19 infection associated with post-COVID-19 condition after 3 months – a questionnaire survey

Figures & data

Figure 1. Consort chart.

Table 1. Descriptive analysis of the main variables used in the study.

	Analysis group				Study sample
	Female		Male		Female		Male
	n	%	n	%	n	%	n	%
Age
	55	5.8	41	6.1	72	7.1	55	7.2
18–29	138	14.6	85	12.7	146	14.3	91	12.0
30–39	129	13.7	107	16.0	136	13.3	114	15.0
40–49	159	16.9	94	14.1	167	16.4	106	13.9
50–59	228	24.2	164	24.5	239	23.5	176	23.2
60–69	140	14.8	89	13.3	151	14.8	108	14.2
70–79	54	5.7	61	9.1	59	5.8	76	10.0
80+	40	4.2	28	4.2	49	4.8	34	4.5
Education (ISCED)
Low (1, 2)	113	12.0	71	10.6	134	13.2	84	11.1
Medium (3, 4)	495	52.5	307	45.9	528	51.8	345	45.4
High (5, 6)	312	33.1	269	40.2	329	32.3	301	39.6
Missing	23	2.4	22	3.3	28	2.7	30	3.9
Weight status (BMI, kg/m²)^a
Normal (<25)	512	54.3	281	42.0	564	55.3	318	41.8
Overweight (25–30)	243	25.8	265	39.6	255	25.0	298	39.2
Obese (30+)	186	19.7	120	17.9	197	19.3	140	18.4
Missing	2	0.2	3	0.4	3	0.3	4	0.5
Smoking status
Never smoked	563	59.7	373	55.8	619	60.7	420	55.3
Current or former	380	40.3	296	44.2	400	39.3	340	44.7
Pre-existing conditions
0	503	53.3	340	50.8	549	53.9	381	50.1
1	217	23.0	164	24.5	235	23.1	185	24.3
2	118	12.5	85	12.7	121	11.9	99	13.0
	105	11.1	80	12.0	114	11.2	95	12.5
Physician consulted because of Covid-19
No	698	74.0	543	81.2	774	76.0	634	83.4
Yes	245	26.0	126	18.8	245	24.0	126	16.6
Hospitalized for Covid-19
No	880	93.3	618	92.4	956	93.8	709	93.3
Yes	63	6.7	51	7.6	63	6.2	51	6.7
Number of symptoms at time of infection
0	0	0.0	0	0.0	76	7.5	91	12.0
1–2	191	20.3	178	26.6	191	18.7	178	23.4
3–4	339	35.9	266	39.8	339	33.3	266	35.0
5–6	309	32.8	192	28.7	309	30.3	192	25.3
7+	104	11.0	33	4.9	104	10.2	33	4.3
Number of symptoms at time of interview
0	453	48.0	418	62.5	529	51.9	509	67.0
1–2	328	34.8	191	28.6	328	32.2	191	25.1
3–4	133	14.1	54	8.1	133	13.1	54	7.1
5+	29	3.1	6	0.9	28	2.8	6	0.8
All	943	100.0	669	100.0	1019	100.0	760	100.0

^aCalculated from weight and height as reported in questionnaire.

Table 2. Sample composition stratified by age and sex in comparison to all confirmed cases of SARSCoV-2 officially registered by RKI [12] in the City of Bremen (Germany) between March, 1^st, 2020 and January, 31^st, 2021.

Age group	Female			Male			Total
	N	%	% RKI	N	%	% RKI
0 - 4	4	0.00	0.01	7	0.00	0.01	11
5 - 14	47	0.03	0.03	33	0.02	0.03	80
15 - 34	239	0.13	0.18	177	0.10	0.19	416
35 - 59	470	0.26	0.19	325	0.18	0.19	795
60 - 79	210	0.12	0.06	184	0.10	0.06	394
80+	49	0.03	0.04	34	0.02	0.02	83
Sum	1019	0.57	0.51	760	0.43	0.49	1779

Figure 2. Symptoms reported at the time of infection (dark gray) and the time of interview (light gray) for females (hatching) and males (no hatching).

Figure 3. Percentage of symptoms reported at time of infection that were still persistent at time of the interview (dark gray) and percentage of symptoms that were newly reported at the time of interview (light gray).

Table 3. Odds ratios (95% CIs) for reporting a post-COVID-19 for the analysis group (N = 1,612) condition estimated from a multivariable logistic regression model.

	Post-COVID-19 condition
	No		Yes
	n	%	n	%	OR	95% CI
Sex
Male	611	91.3	58	8.7	Ref.
Female	798	84.6	145	15.4	1.54	(1.05, 2.24)
Age (mean, sd)	46.6	18.9	51.7	15.1	1.00	(0.99, 1.01)
Fatigue
No	417	95.9	18	4.1	Ref.
Yes	992	84.3	185	15.7	1.75	(1.00, 3.06)
Breathing difficulties
No	1051	94.3	63	5.7	Ref.
Yes	358	71.9	140	28.1	4.02	(2.80, 5.77)
Cognitive symptoms
No	1377	88.4	181	11.6	Ref.
Yes	32	59.3	22	40.7	2.98	(1.48, 6.02)
Digestive symptoms
No	1098	90.2	119	9.8	Ref.
Yes	311	78.7	84	21.3	1.24	(0.86, 1.80)
Fever/Chills
No	665	89.6	77	10.4	Ref.
Yes	744	85.5	126	14.5	0.87	(0.61, 1.25)
Head-& Boneaches
No	454	94.4	27	5.6	Ref.
Yes	955	84.4	176	15.6	2.06	(1.25, 3.42)
Other respiratory symptoms
No	451	90.9	45	9.1	Ref.
Yes	958	85.8	158	14.2	1.16	(0.76, 1.76)
Changes to sense of smell and taste
No	609	89.0	75	11.0	Ref.
Yes	800	86.2	128	13.8	0.91	(0.64, 1.31)
Heart & circulatory problems
No	1375	88.1	186	11.9	Ref.
Yes	34	66.7	17	33.3	1.51	(0.71, 3.24)
Other Covid-19-related symptoms
No	1340	87.9	184	12.1	Ref.
Yes	69	78.4	19	21.6	0.84	(0.44, 1.61)
Other unspecific symptoms
No	1314	88.3	174	11.7	Ref.
Yes	95	76.6	29	23.4	1.37	(0.78, 2.39)
High blood pressure or hypertension
No	1041	88.6	134	11.4	Ref.
Yes	368	84.2	69	15.8	0.87	(0.58, 1.31)
Other cardiovascular diseases^a
No	1307	88.0	179	12.0	Ref.
Yes	102	81.0	24	19.0	0.80	(0.43, 1.50)
Diabetes mellitus
No	1335	87.7	187	12.3	Ref.
Yes	74	82.2	16	17.8	0.72	(0.36, 1.44)
Asthma
No	1268	88.3	168	11.7	Ref.
Yes	141	80.1	35	19.9	1.17	(0.67, 2.05)
Chronic lung disease (e.g. COPD)
No	1302	88.6	168	11.4	Ref.
Yes	107	75.4	35	24.6	1.49	(0.83, 2.66)
Chronic bronchitis
No	1345	88.4	177	11.6	Ref.
Yes	64	71.1	26	28.9	1.30	(0.71, 2.38)
Cancer
No	1323	88.0	180	12.0	Ref.
Yes	86	78.9	23	21.1	1.65	(0.79, 3.48)
Currently receiving medical treatment for cancer
No	1377	87.8	192	12.2	Ref.
Yes	32	74.4	11	25.6	0.83	(0.28, 2.51)
Weakened immune system^b
No	1322	88.5	172	11.5	Ref.
Yes	87	73.7	31	26.3	1.57	(0.92, 2.69)
Chronic liver disease
No	1385	87.6	196	12.4	Ref.
Yes	24	77.4	7	22.6	0.99	(0.34, 2.90)
Adiposity (diagnosed by physician)
No	1313	88.1	177	11.9	Ref.
Yes	96	78.7	26	21.3	1.06	(0.56, 2.01)
Education (ISCED)
Low (ISCED 1, 2)	161	87.5	23	12.5	1.39	(0.74, 2.58)
Medium (ISCED 3, 4)	683	85.2	119	14.8	1.24	(0.84, 1.84)
High (ISCED 5, 6)	524	90.2	57	9.8	Ref.
Missing	41	91.1	4	8.9	1.04	(0.28, 3.90)
Obese (BMI >30 kg/m²)^c
No	1164	89.1	142	10.9	Ref.
Yes	245	80.1	61	19.9	1.53	(0.97, 2.41)
Smoking status
Never smoked	837	89.4	99	10.6	Ref.
Current or ex-smoker	572	84.6	104	15.4	1.19	(0.84, 1.69)
Physician consulted
No	1121	90.3	120	9.7	Ref.
Yes	288	77.6	83	22.4	2.25	(1.54, 3.30)
Hospitalized
No	1334	89.1	164	10.9	Ref.
Yes	75	65.8	39	34.2	3.68	(2.08, 6.49)
Time interval infection to interview
90–120 days	481	85.4	82	14.6	Ref.
120–180 days	425	87.8	59	12.2	0.71	(0.47, 1.08)
	503	89.0	62	11.0	0.63	(0.42, 0.95)
All	1409	87.4	203	12.6

^aIncludes circulatory problems of the heart, stenosis of the coronary arteries, angina pectoris, heart attack, heart failure or heart insufficiency, stroke.

^bMedical conditions associated with weakened immune system or under medications that weaken the immune system.

^cCalculated from weight and height as reported in questionnaire.

Robert Koch-Institut (RKI). COVID-19 Datenhub. https://npgeo-corona-npgeo-de.hub.arcgis.com/datasets/f7bdcbe7188545daabe65e6c9e2a4379_0/explore

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Data availability statement

Datasets used in this study are available from the corresponding author (SR) upon reasonable request.