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  <xs:element id="vtl_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueRollForward" abstract="true" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="vtl_DuaneNashMDJDMBAMember" abstract="true" name="DuaneNashMDJDMBAMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="vtl_Dr.VittMember" abstract="true" name="Dr.VittMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="vtl_ExecutiveChairmanAgreementMember" abstract="true" name="ExecutiveChairmanAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="vtl_SalaryAndWageOfficerMonthlyBaseSalary" abstract="false" name="SalaryAndWageOfficerMonthlyBaseSalary" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="vtl_SalaryAndWageRetentionBonusAgreement" abstract="false" name="SalaryAndWageRetentionBonusAgreement" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="vtl_SalaryAndWageRetentionBonusAgreementTerminationPayoutPeriod" abstract="false" name="SalaryAndWageRetentionBonusAgreementTerminationPayoutPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="vtl_ReportableSegmentMember" abstract="true" name="ReportableSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="vtl_ClinicalProductCandidates" abstract="false" name="ClinicalProductCandidates" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="vtl_PreClinicalProductCandidates" abstract="false" name="PreClinicalProductCandidates" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="vtl_SalaryAndWageOfficerMonthlyRetainerServicesAmount" abstract="false" name="SalaryAndWageOfficerMonthlyRetainerServicesAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="vtl_SalaryAndWageOfficerBaseSalaryPeriod" abstract="false" name="SalaryAndWageOfficerBaseSalaryPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="vtl_NumberOfInstallments" abstract="false" name="NumberOfInstallments" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="vtl_SalaryAndWageOfficerAggregateSalary" abstract="false" name="SalaryAndWageOfficerAggregateSalary" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="vtl_SalaryAndWageOfficerRemainingSalaryPeriod" abstract="false" name="SalaryAndWageOfficerRemainingSalaryPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="vtl_NumberOfMonthlyInstallments" abstract="false" name="NumberOfMonthlyInstallments" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="vtl_SalaryAndWageLumpSumBonusPayment" abstract="false" name="SalaryAndWageLumpSumBonusPayment" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="vtl_SalaryAndWageLumpSumBonusPaymentPercentage" abstract="false" name="SalaryAndWageLumpSumBonusPaymentPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="vtl_HealthcareCosts" abstract="false" name="HealthcareCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="vtl_SalaryAndWageReimbursementEffectivePeriod" abstract="false" name="SalaryAndWageReimbursementEffectivePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="vtl_SalaryAndWageOutstandingEquityAwardsVestedPercentage" abstract="false" name="SalaryAndWageOutstandingEquityAwardsVestedPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
</xs:schema>
