Cases of cVDPV now exceed wild-type cases, making it desirable to discontinue the use of the oral polio vaccine as soon as safely possible and instead use other types of polio vaccines. Afghanistan and Pakistan
The last remaining region with wild polio cases are the South Asian countries Afghanistan and Pakistan. During 2011, the CIA ran a fake hepatitis vaccination clinic in Abbottabad, Pakistan in an attempt to locate Osama bin Laden. This destroyed trust in vaccination programs in the region. There were attacks and deaths among vaccination workers; 66 vaccinators were killed in 2013 and 2014. In Afghanistan, the Taliban banned house-to-house polio vaccination between 2018 and 2021. These factors have set back efforts to eliminate polio by means of vaccination in these countries.In Afghanistan, 80 cases of polio were reported from 35 districts during 2011. Incidence over the subsequent 10 years has declined to just 4 cases in 2 districts during 2021.In Pakistan, cases dropped by 97 percent from 2014 to 2018; reasons include 440 million dirham support from the United Arab Emirates to vaccinate more than ten million children, changes in the military situation, and arrests of some of those who attacked polio workers. During 2021 only one case of wild polio was detected in Pakistan. Americas
The Americas were declared polio-free in 1994. The last known case was a boy in Peru in 1991.
A blighted ovum is a pregnancy in which the embryo never develops or develops and is reabsorbed. In a normal pregnancy, an embryo would be visible on an ultrasound by six weeks after the womans last menstrual period. Anembryonic gestation is one of the causes of miscarriage of a pregnancy.A blighted ovum or anembryonic gestation is characterized by a normal-appearing gestational sac, but the absence of an embryo. It likely occurs as a result of early embryonic death with continued development of the trophoblast. When small, the sac cannot be distinguished from the early normal pregnancy, as there may be a yolk sac, though a fetal pole is not seen. For diagnosis, the sac must be of sufficient size that the absence of normal embryonic elements is established. The criteria depends on the type of ultrasound exam performed. A pregnancy is anembryonic if a transvaginal ultrasound reveals a sac with a mean gestational sac diameter (MGD) greater than 25 mm and no yolk sac, or an MGD >25 mm with no embryo. Transabdominal imaging without transvaginal scanning may be sufficient for diagnosing early pregnancy failure when
an embryo whose crown–rump length is 15 mm or more has no visible cardiac activity. See also
Ovum
Products of conception

References
External links

Blighted Ovum on WebMD
Anembryonic pregnancy on Radiopaedia.org
Johnson, MR; Riddle, AF; Sharma, V; Collins, WP; Nicolaides, KH; Grudzinskas, JG (January 1993). "Placental and ovarian hormones in anembryonic pregnancy". Human Reproduction (Oxford, England). 8 (1): 112–5. doi:10.1093/oxfordjournals.humrep.a137857. PMID 8458911.