On hot summer days, few things are more refreshing than a dip in the pool. But have you ever wondered if the pool is as clean as that crystal blue water appears?
As an immunologist and infectious disease specialist, I study how germs spread in public spaces and how to prevent the spread. I even teach a course called “The Infections of Leisure” where we explore the risks tied to recreational activities and discuss precautions, while also taking care not to turn students into germophobes.
kAm$H:>>:?8[ 6DA64:2==J :? AF3=:4 A@@=D 2?5 H2E6C A2C<D[ 4@>6D H:E9 :ED @H? F?:BF6 D6E @7 C:D<D — 7C@> >:?@C D<:? :CC:E2E:@?D E@ 82DEC@:?E6DE:?2= :?764E:@?D] qFE DH:>>:?8 2=D@ 92D 2 A=6E9@C2 @7 A9JD:42=[ D@4:2= 2?5 >6?E2= k2 9C67lQ9EEADi^^E964@?G6CD2E:@?]4@>^DH:>>:?8\8:G6D\J@FC\3C2:?\2\3@@DE\3FE\D4:6?E:DED\5@?E\<?@H\J6E\H9J\:ED\36EE6C\E92?\@E96C\26C@3:4\24E:G:E:6D\`ecahfQm962=E9 36?67:EDk^2m] (:E9 D@>6 <?@H=6586 2?5 2 =:EE=6 G:8:=2?46[ J@F 42? 6?;@J E96 H2E6C H:E9@FE H@CCJ:?8 23@FE H92E >:89E 36 =FC<:?8 36?62E9 E96 DFC7246]k^Am
k9am%96 C62=:EJ @7 A@@= 86C>Dk^9am
kAm$F>>6C ?6HD 9625=:?6D 2?5 D@4:2= >65:2 A@DED k2 9C67lQ9EEADi^^HHH]A@AD4:]4@>^DH:>>:?8\A@@=D\2C6\8C@DD^Qm@7E6? DA@E=:89E E96 “:4<\724E@C”k^2m @7 4@>>F?2= DH:>>:?8 DA246D] %96D6 4@?46C?D 5@ 92G6 D@>6 >6C:E]k^Am
kAm%96 8@@5 ?6HD :D E92E k2 9C67lQ9EEADi^^HHH]496>:42=D276EJ724ED]@C8^962=E9\2?5\D276EJ^9@H\49=@C:?6\<66AD\A@@=D\D276\7@C\DF>>6CE:>6\7F?^Qm49=@C:?6[ H9:49 :D H:56=J FD65 :? A@@=Dk^2m[ :D 67764E:G6 2E <:==:?8 >2?J A2E9@86?D] %96 ?@E\D@\8@@5 ?6HD :D E92E 49=@C:?6 5@6D ?@E H@C< :?DE2?E=J – 2?5 :E 5@6D?’E <:== 6G6CJE9:?8]k^Am
kAmtG6CJ DF>>6C[ E96 k2 9C67lQ9EEADi^^HHH]454]8@G^962=E9J\DH:>>:?8^AC6G6?E:@?^:?56I]9E>=Qmr6?E6CD 7@C s:D62D6 r@?EC@= 2?5 !C6G6?E:@?k^2m :DDF6D 2=6CED 23@FE DH:>>:?8\C6=2E65 @FE3C62<D @7 :==?6DD 42FD65 3J 6IA@DFC6 E@ 86C>D :? AF3=:4 A@@=D 2?5 H2E6C A2C<D] p a_ab rsr C6A@CE k2 9C67lQ9EEADi^^HHH]454]8@G^>>HC^G@=F>6D^f_^HC^>>f_a_2`]9E>QmEC24<65 @G6C a__ A@@=\2DD@4:2E65 @FE3C62<Dk^2m 7C@> a_`d E@ a_`h 24C@DD E96 &]$][ 27764E:?8 >@C6 E92? b[e__ A6@A=6] %96D6 @FE3C62<D :?4=F565 D<:? :?764E:@?D[ C6DA:C2E@CJ :DDF6D[ 62C :?764E:@?D 2?5 82DEC@:?E6DE:?2= 5:DEC6DD] |2?J @7 E96 @FE4@>6D 7C@> DF49 :?764E:@?D 2C6 >:=5[ 3FE D@>6 42? 36 D6C:@FD]k^Am
k9amv6C>D 2?5 5:D:?764E2?EDk^9am
kAmtG6? :? 2 A@@= E92E’D AC@A6C=J EC62E65 H:E9 49=@C:?6[ D@>6 A2E9@86?D 42? =:?86C 7@C >:?FE6D E@ 52JD] ~?6 @7 E96 >@DE 4@>>@? 4F=AC:ED :D k2 9C67lQ9EEADi^^5@:]@C8^`_]a`ee^H9]a_`e]`e_Qmk6>mrCJAE@DA@C:5:F>k^6>m[ 2 >:4C@D4@A:4 86C>k^2m E92E 42FD6D H2E6CJ 5:2CC962] %9:D D:?8=6\46==65 A2C2D:E6 92D 2 E@F89 @FE6C D96== E92E 2==@HD :E E@ DFCG:G6 :? 49=@C:?6\EC62E65 H2E6C 7@C k2 9C67lQ9EEADi^^?6HD?6EH@C<]>2J@4=:?:4]@C8^5:D4FDD:@?^:?764E:@FD\5:D62D6D\<66A\4CJAE@DA@C:5:F>\@FE\@7\E96\A@@=^QmFA E@ `_ 52JDk^2m] xE DAC625D H96? 7642= >2EE6C — @7E6? 7C@> D@>6@?6 H:E9 5:2CC962 — 6?E6CD E96 H2E6C 2?5 :D DH2==@H65 3J 2?@E96C DH:>>6C] tG6? 2 E:?J 2>@F?E[ :?G:D:3=6 E@ E96 6J6[ 42? :?764E 5@K6?D @7 A6@A=6]k^Am
k7:8FC6mk2 2C:2\=236=lQ+@@>23=6 :>286Q 9C67lQ9EEADi^^:>286D]E964@?G6CD2E:@?]4@>^7:=6D^eg`eae^@C:8:?2=^7:=6\a_ad_faa\de\2Ff6g@];A8n:I=:3lC3\c]`]`U2>AjBlcdU2>Aj2FE@l7@C>2EU2>Aj7:El4=:AQmk:>8 2=ElQr@==64E:@? @7 G:DF2= DJ>3@=D 7@C A@@= CF=6DQ DC4lQ9EEADi^^:>286D]E964@?G6CD2E:@?]4@>^7:=6D^eg`eae^@C:8:?2=^7:=6\a_ad_faa\de\2Ff6g@];A8n:I=:3lC3\c]`]`U2>AjBlcdU2>Aj2FE@l7@C>2EU2>Aj7:El4=:AQ ^mk^2mk7:842AE:@?m$9@H6C:?8 367@C6 2?5 27E6C DH:>>:?8 :? 2 AF3=:4 A@@= 96=AD 2G@:5 3@E9 3C:?8:?8 :? 2?5 E2<:?8 @FE A2E9@86?D 2?5 3@5J DF3DE2?46D] k2 9C67lQ9EEADi^^HHH]86EEJ:>286D]4@>^56E2:=^:==FDEC2E:@?^DH:>>:?8\A@@=\CF=6D\DJ>3@=\4@==64E:@?\C@J2=EJ\7C66\:==FDEC2E:@?^a`ddc`achfQmw27:5 u:C>2? $J2C:7^:$E@4< G:2 v6EEJ x>286D !=FDk^2mk^7:842AE:@?mk^7:8FC6m
kAmp?@E96C 4@>>@? 86C> :D k2 9C67lQ9EEADi^^5@:]@C8^`_]a`ee^H9]a_`a]_a_Qmk6>m!D6F5@>@?2D 26CF8:?@D2k^6>m[ 2 324E6C:F>k^2m E92E 42FD6D 9@E EF3 C2D9 2?5 k2 9C67lQ9EEADi^^E964@?G6CD2E:@?]4@>^DH:>>6CD\62C\5@6D?E\;FDE\27764E\DH:>>6CD\EH@\62C\5@4E@CD\6IA=2:?\H92E\J@F\?665\E@\<?@H\23@FE\E9:D\A2:?7F=\4@?5:E:@?\`gha`bQmDH:>>6C’D 62Ck^2m] ':CFD6D =:<6 k2 9C67lQ9EEADi^^5@:]@C8^`_]`_`f^$_hd_aegg_e__fbf_Qm?@C@G:CFDk^2m 2?5 k2 9C67lQ9EEADi^^5@:]@C8^`_]bbh_^:;6CA9`e_a_`eeQm256?@G:CFDk^2m 42? 2=D@ =:?86C :? A@@= H2E6C 2?5 42FD6 :==?6DD]k^Am
kAm$H:>>6CD :?EC@5F46 2 C2?86 @7 3@5:=J C6D:5F6D E@ E96 H2E6C[ :?4=F5:?8 DH62E[ FC:?6[ @:=D 2?5 D<:? 46==D] %96D6 DF3DE2?46D[ 6DA64:2==J DH62E 2?5 FC:?6[ k2 9C67lQ9EEADi^^5@:]@C8^`_]`_`e^;]:;969]a_``]_f]_`aQm:?E6C24E H:E9 49=@C:?6 E@ 7@C> 496>:42= 3JAC@5F4EDk^2m 42==65 49=@C2>:?6D E92E >2J A@D6 962=E9 C:D<D]k^Am
kAm%96D6 3JAC@5F4ED 2C6 C6DA@?D:3=6 7@C E92E DEC@?8 49=@C:?6 D>6==] p 4=62? A@@= D9@F=5 24EF2==J =24< 2 DEC@?8 49=@C:?6 @5@C[ 2D H6== 2D 2?J @E96C D>6==D[ @7 4@FCD6] xE :D 2 4@>>@? >JE9 E92E 2 DEC@?8 49=@C:?6 D>6== :D 2 8@@5 D:8? @7 2 4=62? A@@=] x? 724E[ :E >2J 24EF2==J 36 2 C65 7=28 E92E >62?D E96 @AA@D:E6 – E92E E96 H2E6C :D 4@?E2>:?2E65 2?5 D9@F=5 A6C92AD 36 2G@:565]k^Am
k9amw@H E@ A=2J :E D276 2E 2 AF3=:4 A@@=k^9am
kAm|@DE A@@=\C6=2E65 C:D<D 42? 36 C65F465 H:E9 D:>A=6 AC642FE:@?D 3J 3@E9 E96 A@@= DE277 2?5 DH:>>6CD] p?5 H9:=6 >@DE A@@=\C6=2E65 :==?6DD6D H@?’E <:== J@F[ ?@ @?6 H2?ED E@ DA6?5 E96:C G242E:@? @C 2 H66< @7 362FE:7F= DF>>6C 52JD :? E96 32E9C@@>]k^Am
kAm%96D6 `_ E:AD 42? 96=A J@F 2G@:5 86C>D 2E E96 A@@=ik^Am
kF=mk=:mkAm$9@H6C 367@C6 DH:>>:?8] #:?D:?8 @77 7@C 2E =62DE @?6 >:?FE6 C6>@G6D >@DE 5:CE 2?5 @:=D @? E96 3@5J E92E k2 9C67lQ9EEADi^^HHH]454]8@G^962=E9J\DH:>>:?8^AC6G6?E:@?^AC6G6?E:?8\5:2CC962=\:==?6DD6D]9E>=QmC65F46 49=@C:?6’D 67764E:G6?6DDk^2m]k^Amk^=:mk=:mkAmpG@:5 E96 A@@= :7 J@F’C6 D:4<[ 6DA64:2==J :7 J@F 92G6 5:2CC962 @C 2? @A6? H@F?5] v6C>D 42? DAC625 BF:4<=J :? H2E6C]k^Amk^=:mk=:mkAm%CJ E@ k2 9C67lQ9EEADi^^5@:]@C8^`_]a`ee^H9]a_`f]addQm<66A H2E6C @FE @7 J@FC >@FE9k^2m E@ >:?:>:K6 E96 C:D< @7 :?86DE:?8 86C>D]k^Amk^=:mk=:mkAms@?’E DH:> :7 J@F 92G6 5:2CC962 E@ 96=A AC6G6?E E96 DAC625 @7 86C>D]k^Amk^=:mk=:mkAmx7 5:28?@D65 H:E9 k2 9C67lQ9EEADi^^HHH]454]8@G^4CJAE@DA@C:5:F>^23@FE^:?56I]9E>=Qm4CJAE@DA@C:5:@D:Dk^2m[ @7E6? 42==65 “4CJAE@[” H2:E EH@ H66<D 27E6C 5:2CC962 DE@AD 367@C6 C6EFC?:?8 E@ E96 A@@=]k^Amk^=:mk=:mkAm%2<6 7C6BF6?E 32E9C@@> 3C62<D] u@C 49:=5C6? 2?5 25F=ED 2=:<6[ C68F=2C 32E9C@@> 3C62<D 96=A AC6G6?E 244:56?ED :? E96 A@@=]k^Amk^=:mk=:mkAmr964< 5:2A6CD 9@FC=J 2?5 492?86 E96> 2H2J 7C@> E96 A@@= E@ AC6G6?E 7642= 4@?E2>:?2E:@?]k^Amk^=:mk=:mkAmsCJ J@FC 62CD E9@C@F89=J 27E6C DH:>>:?8 E@ k2 9C67lQ9EEADi^^HHH]2>2\2DD?]@C8^56=:G6C:?8\42C6^A@AF=2E:@?\42C6^H92E\5@4E@CD\H:D9\A2E:6?ED\<?6H\23@FE\DH:>>6C\D\62CQm96=A AC6G6?E DH:>>6C’D 62Ck^2m]k^Amk^=:mk=:mkAms@?’E DH:> H:E9 2? @A6? H@F?5 – @C 2E =62DE >2<6 DFC6 :E’D 4@>A=6E6=J 4@G6C65 H:E9 2 H2E6CAC@@7 32?5286 E@ AC@E64E 3@E9 J@F 2?5 @E96CD]k^Amk^=:mk=:mkAm$9@H6C 27E6C DH:>>:?8 E@ C6>@G6 86C>D 7C@> J@FC D<:?]k^Amk^=:mk^F=m
kAmk6>m%9:D 2CE:4=6 :D C6AF3=:D965 7C@> k2 9C67lQ9EEAi^^E964@?G6CD2E:@?]4@>^FDnFE>0D@FC46l{66U2>AjFE>0>65:F>lC6=2E65\=:?<U2>AjFE>042>A2:8?lC6=2E65\=:?<\_U2>AjFE>04@?E6?El2CE:4=6\ae_hheQm%96 r@?G6CD2E:@?k^2m[ 2 ?@?AC@7:E[ :?56A6?56?E ?6HD @C82?:K2E:@? 3C:?8:?8 J@F 724ED 2?5 ECFDEH@CE9J 2?2=JD:D E@ 96=A J@F >2<6 D6?D6 @7 @FC 4@>A=6I H@C=5] xE H2D HC:EE6? 3Ji k2 9C67lQ9EEADi^^E964@?G6CD2E:@?]4@>^AC@7:=6D^=:D2\4F492C2\acb_gbenFE>0D@FC46l{66U2>AjFE>0>65:F>lC6=2E65\=:?<U2>AjFE>042>A2:8?l3J=:?6\=:?<U2>AjFE>04@?E6?El2CE:4=6\ae_hheQm{:D2 rF492C2k^2m[ k6>mk2 9C67lQ9EEADi^^E964@?G6CD2E:@?]4@>^:?DE:EFE:@?D^BF:??:A:24\F?:G6CD:EJ\a_banFE>0D@FC46l{66U2>AjFE>0>65:F>lC6=2E65\=:?<U2>AjFE>042>A2:8?l3J=:?6\=:?<U2>AjFE>04@?E6?El2CE:4=6\ae_hheQm"F:??:A:24 &?:G6CD:EJk^2mk^6>mk^6>mk^Am
kAmkDEC@?8m#625 >@C6ik^DEC@?8mk^Am
kF=mk=:mk2 9C67lQ9EEAi^^E964@?G6CD2E:@?]4@>^49=@C:?6\:D\2\9:89=J\FD67F=\496>:42=\E92ED\2=D@\6IEC6>6=J\52?86C@FD\96C6D\H92E\E@\<?@H\23@FE\DE2J:?8\D276\2C@F?5\:E\a`bhhgnFE>0D@FC46l{66U2>AjFE>0>65:F>lC6=2E65\=:?<U2>AjFE>042>A2:8?lC6=2E65\=:?<_U2>AjFE>04@?E6?El2CE:4=6\ae_hheQmr9=@C:?6 :D 2 9:89=J FD67F= 496>:42= E92E’D 2=D@ 6IEC6>6=J 52?86C@FD − 96C6’D H92E E@ <?@H 23@FE DE2J:?8 D276 2C@F?5 :Ek^2mk^=:mk=:mk2 9C67lQ9EEAi^^E964@?G6CD2E:@?]4@>^>2?F\;F>A:?8\E96\A9JD:4D\369:?5\>2<:?8\9F>@?8@FD\DA=2D96D\:?\E96\A@@=\addgbfnFE>0D@FC46l{66U2>AjFE>0>65:F>lC6=2E65\=:?<U2>AjFE>042>A2:8?lC6=2E65\=:?<`U2>AjFE>04@?E6?El2CE:4=6\ae_hheQm‘|2?F ;F>A:?8’i %96 A9JD:4D 369:?5 >2<:?8 9F>@?8@FD DA=2D96D :? E96 A@@=k^2mk^=:mk=:mk2 9C67lQ9EEAi^^E964@?G6CD2E:@?]4@>^E96\7@C8@EE6?\9:DE@CJ\@7\D68C682E65\DH:>>:?8\A@@=D\2?5\2>FD6>6?E\A2C<D\``hdgenFE>0D@FC46l{66U2>AjFE>0>65:F>lC6=2E65\=:?<U2>AjFE>042>A2:8?lC6=2E65\=:?<aU2>AjFE>04@?E6?El2CE:4=6\ae_hheQm%96 7@C8@EE6? 9:DE@CJ @7 D68C682E65 DH:>>:?8 A@@=D 2?5 2>FD6>6?E A2C<Dk^2mk^=:mk^F=m
kA 4=2DDlQ7:?6\AC:?EQmk6>mkDA2?m{:D2 rF492C2 :D 277:=:2E65 H:E9 p>6C:42? $@4:6EJ 7@C |:4C@3:@=@8Jk^DA2?mk^6>mk^Am
kAmk:>8 DC4lQ9EEADi^^4@F?E6C]E964@?G6CD2E:@?]4@>^4@?E6?E^ae_hhe^4@F?E]8:7n5:DEC:3FE@Cl=66Q DEJ=6lQ96:89Ei`AIjH:5E9i`AIjQ 2=ElQQ ^mk^Am
