COVID-19 and Homelessness: Low Vaccination Rate, High Prevalence

The negative consequences of the SARS-CoV-2 pandemic are unevenly distributed in the population. Different pre-existing comorbidities can, for example, be associated with an unfavorable course of COVID-19. Social dimensions are also of importance. It is well known that people with a lower social status get ill more often. International studies have shown for such people an increased risk for a more severe course with higher mortality (1). Little is known in this regard about the group of homeless people, which is already disadvantaged by strongly increased morbidity and mortality (2).

People without fixed abode do not have a residential (main) address that is ensured by a rental/lettings contract. Such persons seek shelter in emergency shelters, women‘s refuges, homeless shelter buses, hotels, or other places. Homeless people in the stricter sense do not have any accommodation—they live and sleep out in the open. Exact numbers for these two groups do not exist. The present project aims to improve knowledge about homeless people in Cologne by presenting facts about COVID-19.

Methods

The study reports a collection of prevalence rates of COVID-19 in 2021 (7 May to 16 May 2021, 25 August to 18 September 2021, 11 December to 20 December 2021). It therefore overlaps the so called third and fourth waves. The project had previously received approval from the institutional review board of Düsseldorf University Hospital (2021–1489). Preliminary data from the first study period have already been published (3).

Subjects were included in the study in an institution providing day care for people with no fixed abode (Gulliver) as well as a charitable find and treat service providing medical care on the streets. After consent and history taking, a SARS-CoV-2 polymerase chain reaction (PCR) test and multiplex PCR for respiratory viruses was carried out for a pharyngeal swab and a sputum specimen (taken by using Salivette swabs) (3). Initially, 10 pools of specimens were produced, and if pools tested positive, individual analyses were undertaken. The repeat testing of subjects in a later data collection phase of the study was permitted. All participants received 5 Euro as an “expense allowance.”

Results

303 subjects were included in the study. Table 1 shows the baseline parameters. For the vaccination history and the virological analyses, a total of 355 tests were undertaken in the three phases of the study in this group of subjects. Table 2 shows these results. SARS-CoV-2 was identified in nine persons; these persons were asymptomatic. The results of the swabs and the Salivette tests were consistent. The determined viral loads (measured in ct values [ct=cycle threshold] of the positive results were between ct 19.2 and ct 36.3. In four cases the alpha variant was identified; in the cases, the delta variant; and two specimens could not be differentiated. All persons who had tested positive and their contacts were actively offered isolation in an isolation facility specially designated by the City of Cologne for people without fixed abode. Eight subjects with symptoms typical of COVID-19 had negative test results.

Table 1. Patient characteristics of the sample.

Subjects	303
Sex distribution
Male	268 (88.4 %)
Female	35 (11.6 %)
Age distribution (years)
18–39	90 (29.7 %)
40–59	172 (56.8 %)
60–77	41 (13.5 %)
Nationality
Germany	153 (50.5 %)
Poland	65 (21.5 %)
Romania	29 (9.6 %)
Other (Bulgaria, Italy, Lithuania. Czech Republic, Turkey, and others)	56 (18.5 %)
Accommodation
Homeless	197 (65.0 %)
Emergency shelter	29 (9.6 %)
Staying with friends	21 (6.9 %)
Hotel, youth hostel	20 (6.6 %)
Other (sheltered housing. women’s refuge, and others)	36 (11.9 %)
Income status
No income	180 (59.4 %)
Unemployment benefit 2	74 (24.4 %)
Other (pension, social security/aid)	49 (16.2 %)
Insurance status
Member of health insurance scheme	153 (50.5 %)
Not a member of health insurance scheme	147 (48.5 %)
Not applicable	3 (1.0 %)

Table 2. Vaccination status and virological parameters of the study testing phases.

Testing phase	1 (7-16 May 2021)		2 (25 August–18 September 2021		3 (11.–20 December 2021)
Subjects	129		143		83
	%	[95% CI]	%	[95% CI]	%	[95% CI]
COVID-19 vaccination status
Not available	0		1.4	[0.5; 3.3]	0
Unvaccinated	78.3	[71.2; 85.4]	42.0	[33.9; 50.0]	39.8	[29.2; 50.3]
1 x vaccinated	14.0	[8.0; 20.0]	4.2	[0.9; 7.5]	21.7	[12.8; 30.6]
2 x vaccinated	7.8	[3.1; 12.4]	52.4	[44.3; 60.6]	31.3	[21.3; 41.3]
3 x vaccinated	0		0		7.2	[1.7; 12.8]
SARS-CoV-2 test
Positive result	3.1	[0.1; 6.1]	0		6.0	[0.9; 11.1]
Test for respiratory viruses*
Positive result	0		1.4	[0.5; 3.3]	12.0	[5.0; 19.1]

* Coronavirus 229E, Coronavirus OC43, Rhinovirus, Respiratory Syncytial Virus (RSV)

95% CI, 95% confidence interval

Discussion

The study population consisted mostly of men and was characterized by its very low social status. This was illustrated by the fact that 60–65% of participants had no fixed abode nor income; furthermore, about half did not have health insurance. The rate of people from an migration background is also high, at 50%.

The results regarding subjects’ vaccination status were particularly relevant (table 2). A very low vaccination rate was seen in all phases of the study. In the third phase, in December 2021, Germany‘s standing vaccination committee (STIKO) had already established its recommendation of three vaccine doses against SARS-CoV-2 (4). Compared with the vaccination rate in the general population, the rate in study participants was notably lower. In December, 31.3% had received two vaccine doses and 7.2% three (compared with the general population: 69.7% and 29.8%, respectively, on the crucial date[16 December 2021]) (5). The picture is similar for the other periods. In spite of diverse vaccination campaigns in Cologne in 2021, it is of note that the rate of immunized homeless persons at the end of 2021 was completely unsatisfactory (table 2).

In the so called fourth wave, the prevalence of COVID-19 was rather high—6%—in asymptomatic people who mostly lived in the streets. In this period, a nationwide 7-day incidence of 300–400/100 000 (<1%) was reported. However, this rate was derived from laboratory routines and symptomatic patients were included. For this reason, the findings are not directly comparable. No publications are available about prevalence rates in mostly asymptomatic adults, in analogy to our study. For this reason, we additionally used screening tests from Cologne University Hospital from the same time periods for the purpose of comparison, while it can be assumed that patients did not have any symptoms typical of COVID-19. PCR tests from non-internal-medicine patients who had been admitted to a normal ward were selected. Relative to the study phases, we found the following rates of positive SARS-CoV-2 tests: phase 1: 2.6%; phase 2: 1.8%; phase 3: 3.4%). With the exception of the second phase, these results are therefore below those of our study population.

In sum, we can assume that in 2021 the prevalence of COVID-19 was notably higher in people without fixed abode than in the general population.

The rate of homeless people or people without fixed abode in whom respiratory virsuses were found was 12% in December 2021.

Conclusions

Our study is the first to present data on vaccination rates and prevalence rates for COVID-19 in people without fixed abode in Germany. In 2021, the vaccination rate for SARS-CoV-2 in this group was very low, whereas the prevalence of the infection was comparatively high. Both findings underline the fact that homeless people, and among these especially those without fixed abode are at great risk from COVID-19. The inevitable conclusion is that for this vulnerable group, greater efforts will have to be made to improve protection against infection.