<s>
NHS	B-Application
COVID-19	I-Application
is	O
a	O
voluntary	O
contact	B-Application
tracing	I-Application
app	I-Application
for	O
monitoring	O
the	O
spread	O
of	O
the	O
COVID-19	O
pandemic	O
in	O
England	O
and	O
Wales	O
.	O
</s>
<s>
It	O
has	O
been	O
available	O
since	O
24	O
September	O
2020	O
for	O
Android	B-Application
and	O
iOS	B-Application
smartphones	B-Application
,	O
and	O
can	O
be	O
used	O
by	O
anyone	O
aged	O
16	O
or	O
over	O
.	O
</s>
<s>
A	O
pilot	O
deployment	O
was	O
begun	O
in	O
May	O
2020	O
,	O
but	O
on	O
18	O
June	O
development	O
of	O
the	O
app	O
was	O
abandoned	O
in	O
favour	O
of	O
a	O
second	O
design	O
using	O
the	O
Apple/Google	B-Application
Exposure	I-Application
Notification	I-Application
system	I-Application
.	O
</s>
<s>
Scotland	O
and	O
Northern	O
Ireland	O
have	O
separate	O
contact	B-Application
tracing	I-Application
apps	I-Application
.	O
</s>
<s>
The	O
Android	B-Application
app	O
is	O
coded	O
in	O
Kotlin	B-Language
,	O
and	O
the	O
iOS	B-Application
app	O
in	O
Swift	B-Application
.	O
</s>
<s>
The	O
backend	O
uses	O
Java	B-Language
and	O
is	O
deployed	O
to	O
Amazon	B-Application
Web	I-Application
Services	I-Application
using	O
Terraform	B-General_Concept
.	O
</s>
<s>
The	O
code	O
of	O
the	O
app	O
and	O
back-end	O
is	O
open-source	B-Application
and	O
available	O
on	O
GitHub	O
.	O
</s>
<s>
In	O
March	O
2020	O
,	O
NHSX	O
commissioned	O
a	O
contact	B-Application
tracing	I-Application
app	I-Application
to	O
monitor	O
the	O
spread	O
in	O
the	O
United	O
Kingdom	O
of	O
the	O
coronavirus	O
disease	O
2019	O
(	O
COVID-19	O
)	O
in	O
the	O
2020	O
pandemic	O
,	O
developed	O
by	O
the	O
Pivotal	O
division	O
of	O
American	O
software	O
company	O
VMware	O
.	O
</s>
<s>
The	O
app	O
used	O
a	O
centralised	O
approach	O
,	O
in	O
contrast	O
to	O
the	O
Google	B-Application
/	I-Application
Apple	I-Application
contact	I-Application
tracing	I-Application
project	I-Application
.	O
</s>
<s>
It	O
then	O
used	O
Bluetooth	B-General_Concept
Low	I-General_Concept
Energy	I-General_Concept
(	O
BLE	O
)	O
to	O
record	O
the	O
daily	O
identification	O
number	O
of	O
other	O
users	O
nearby	O
.	O
</s>
<s>
These	O
details	O
were	O
then	O
passed	O
to	O
a	O
central	O
NHS	O
server	B-Application
.	O
</s>
<s>
On	O
18	O
June	O
,	O
Health	O
Secretary	O
Matt	O
Hancock	O
announced	O
development	O
would	O
switch	O
to	O
the	O
Apple/Google	O
system	O
after	O
admitting	O
that	O
Apple	O
's	O
restrictions	O
on	O
usage	O
of	O
Bluetooth	B-Protocol
prevented	O
the	O
app	O
from	O
working	O
effectively	O
.	O
</s>
<s>
At	O
the	O
same	O
press	O
briefing	O
Dido	O
Harding	O
,	O
leader	O
of	O
the	O
UK	O
's	O
test	O
and	O
trace	O
programme	O
,	O
said	O
"	O
What	O
we	O
've	O
done	O
in	O
really	O
rigorously	O
testing	O
both	O
our	O
own	O
Covid-19	B-Application
app	I-Application
and	O
the	O
Google-Apple	O
version	O
is	O
demonstrate	O
that	O
none	O
of	O
them	O
are	O
working	O
sufficiently	O
well	O
enough	O
to	O
be	O
actually	O
reliable	O
to	O
determine	O
whether	O
any	O
of	O
us	O
should	O
self-isolate	O
for	O
two	O
weeks	O
 [ and ] 	O
that	O
's	O
true	O
across	O
the	O
world	O
"	O
.	O
</s>
<s>
The	O
second	O
version	O
of	O
the	O
app	O
,	O
released	O
nationwide	O
,	O
addressed	O
these	O
concerns	O
by	O
employing	O
a	O
decentralised	O
framework	O
,	O
the	O
Apple/Google	B-Application
Exposure	I-Application
Notification	I-Application
system	I-Application
.	O
</s>
<s>
The	O
functionality	O
of	O
the	O
app	O
was	O
also	O
questioned	O
in	O
late	O
April	O
and	O
early	O
May	O
2020	O
,	O
as	O
the	O
software	O
's	O
use	O
of	O
Bluetooth	B-Protocol
required	O
the	O
app	O
to	O
be	O
constantly	O
running	O
,	O
meaning	O
users	O
could	O
not	O
use	O
other	O
apps	O
or	O
lock	O
their	O
device	O
if	O
the	O
app	O
was	O
to	O
function	O
properly	O
.	O
</s>
<s>
By	O
using	O
the	O
Exposure	B-Application
Notification	I-Application
system	O
from	O
Apple	O
and	O
Google	O
,	O
personal	O
data	O
would	O
be	O
decentralised	O
.	O
</s>
<s>
Zuhlke	O
Engineering	O
was	O
awarded	O
"	O
Development	O
Team	O
of	O
the	O
Year	O
"	O
title	O
at	O
UK	O
IT	O
Industry	O
awards	O
in	O
November	O
2021	O
for	O
development	O
of	O
NHS	B-Application
COVID-19	I-Application
application	O
.	O
</s>
<s>
After	O
five	O
weeks	O
,	O
around	O
29	O
October	O
,	O
there	O
had	O
been	O
19	O
million	O
downloads	O
;	O
this	O
was	O
said	O
to	O
equate	O
to	O
around	O
40%	O
of	O
adults	O
with	O
access	O
to	O
a	O
compatible	O
smartphone	B-Application
,	O
which	O
Dido	O
Harding	O
stated	O
was	O
"	O
a	O
better	O
performance	O
than	O
any	O
other	O
country	O
where	O
downloading	O
is	O
n't	O
compulsory	O
"	O
.	O
</s>
<s>
By	O
the	O
end	O
of	O
2020	O
the	O
number	O
of	O
users	O
with	O
the	O
app	O
installed	O
had	O
fallen	O
to	O
13.5million	O
,	O
of	O
whom	O
an	O
estimated	O
11.5million	O
had	O
the	O
app	O
fully	O
operational	O
(	O
Bluetooth	B-Protocol
and	O
notifications	O
turned	O
on	O
,	O
and	O
location	O
sharing	O
enabled	O
if	O
applicable	O
)	O
.	O
</s>
<s>
At	O
that	O
time	O
it	O
was	O
the	O
second	O
most-downloaded	O
free	O
application	O
in	O
the	O
UK	O
in	O
the	O
Apple	O
App	O
store	O
,	O
behind	O
Zoom	B-Application
and	O
above	O
TikTok	B-Application
.	O
</s>
<s>
It	O
was	O
concluded	O
that	O
during	O
the	O
first	O
months	O
of	O
the	O
second	O
wave	O
of	O
the	O
COVID-19	O
pandemic	O
,	O
the	O
1.7	O
million	O
exposure	B-Application
notifications	I-Application
sent	O
by	O
the	O
app	O
prevented	O
around	O
600,000	O
cases	O
of	O
infection	O
in	O
England	O
and	O
Wales	O
between	O
its	O
launch	O
on	O
24	O
September	O
2020	O
and	O
the	O
end	O
of	O
December	O
2020	O
.	O
</s>
<s>
The	O
term	O
pingdemic	O
–	O
a	O
play	O
on	O
ping	O
,	O
meaning	O
notification	B-Application
,	O
and	O
pandemic	O
–	O
became	O
popular	O
in	O
the	O
UK	O
's	O
media	O
as	O
many	O
people	O
,	O
including	O
the	O
Prime	O
Minister	O
and	O
other	O
senior	O
ministers	O
,	O
were	O
affected	O
.	O
</s>
<s>
In	O
March	O
2023	O
,	O
it	O
was	O
reported	O
in	O
the	O
Guardian	O
that	O
the	O
NHS	B-Application
COVID-19	I-Application
app	I-Application
would	O
be	O
decommissioned	O
due	O
to	O
decreasing	O
demand	O
and	O
the	O
end	O
of	O
lockdown	O
restrictions	O
,	O
though	O
vaccine	O
passport	O
functions	O
would	O
remain	O
available	O
in	O
the	O
NHS	B-Application
app	I-Application
.	O
</s>
