UPDATE: According to BBC Sport, Isaac Makwala had food poisoning before the 200m heats. Multiple hotels that are hosting athletes in London have reported several cases of food poisoning during the championship. Makwala received a medical exemption from the 200m so he is eligible to compete in the 400m final on Tuesday.

Wayde van Niekerk's chances of a 200m/400m gold medal sweep just got a lot stronger with the absence of No. 1-ranked Makwala.

The standout from Botswana was scheduled to compete in heat five of the 200m at the IAAF World Championships Monday night in London, but did not show up to the starting line. Makwala ran a world lead of 19.77 in the 200m at the Centro Deportivo Munipical in Madrid on July 14.

Makwala competed through the semifinal of the 400m on Sunday and qualified for the final by winning heat three in 44.30. He is still scheduled to compete against van Niekerk in the 400m final on Tuesday.

Van Niekerk secured his place in the 200m semifinal by winning heat three in 20.16. The 400m Olympic champion has won every round he's competed in so far in London.

Three competitors were disqualified for lane infringements out of the heats--Aaron Brown (Canada), Clarence Munyai (South Africa), and Paul Nalau (South Africa).

Full list of 200m semifinal qualifiers:

POS	ATHLETE	COUNTRY	RESULTS
1	Jereem RICHARDS	TTO	20.05 Q
2	Nethaneel MITCHELL-BLAKE	GBR	20.08 Q
3	Ramil GULIYEV	TUR	20.16 Q
4	Wayde VAN NIEKERK	RSA	20.16 Q
5	Daniel TALBOT	GBR	20.16 Q PB
6	Isiah YOUNG	USA	20.19 Q
7	Ameer WEBB	USA	20.22 Q
8	Akani SIMBINE	RSA	20.26 Q
9	Sydney SIAME	ZAM	20.29 Q NR
10	Likoúrgos-Stéfanos TSÁKONAS	GRE	20.37 Q
11	Yohan BLAKE	JAM	20.39 Q
12	Christophe LEMAITRE	FRA	20.40 Q
13	Kyree KING	USA	20.41 Q
14	Zharnel HUGHES	GBR	20.43 q
15	Kyle GREAUX	TTO	20.48 Q
16	Wilfried KOFFI HUA	CIV	20.49 q
17	Rasheed DWYER	JAM	20.49 Q
18	Abdul Hakim SANI BROWN	JPN	20.52 Q
19	Ján VOLKO	SVK	20.52 Q
20	Alex WILSON	SUI	20.54 Q
21	David LIMA	POR	20.54 q
22	Serhiy SMELYK	UKR	20.58
23	Shota IIZUKA	JPN	20.58 Q
24	Filippo TORTU	ITA	20.59 Q
25	Jonathan QUARCOO	NOR	20.60
26	Warren WEIR	JAM	20.60
27	Winston GEORGE	GUY	20.61 Q
28	Alonso EDWARD	PAN	20.61 SB
29	Ahmed ALI	SUD	20.64
30	Jeffrey JOHN	FRA	20.66
31	Sibusiso MATSENJWA	SWZ	20.67
32	Mark Otieno ODHIAMBO	KEN	20.74
33	Teray SMITH	BAH	20.77
34	Adama JAMMEH	GAM	20.79
35	Jeremy DODSON	SAM	20.81
36	Aldemir DA SILVA JUNIOR	BRA	20.82
37	Salem Eid YAQOOB	BRN	20.84
38	Bernardo BALOYES	COL	20.86
39	Joseph MILLAR	NZL	20.97
40	Burkheart ELLIS JR	BAR	20.99
41	Fabrice DABLA	TOG	21.40
42	Mohamed ALSADI	OMA	21.50
43	Ifeanyi OTUONYE	TKS	21.91
44	Muhd Noor Firdaus AR-RASYID	BRU	22.36
45	Kabongo MULUMBA	COD	23.57 SB
	Aaron BROWN	CAN	DQ
	Clarence MUNYAI	RSA	DQ
	Paul NALAU	VAN	DQ
	Julius Morris	MNT	DNS
	Isaac Makwala	BOT	DNS