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<!-- Creation Date :2022-02-28T14:48:59.9929+00:00 -->
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  <xsd:element id="pcvx_MaximumCommissionPercentageOfGrossProceedsFromCommonStockSold" name="MaximumCommissionPercentageOfGrossProceedsFromCommonStockSold" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_NumberOfFinanceLease" name="NumberOfFinanceLease" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_NumberOfOperatingLease" name="NumberOfOperatingLease" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_NumberOfOptionsExercisedExcludesOptionsExercisedFromNpln" name="NumberOfOptionsExercisedExcludesOptionsExercisedFromNpln" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_NumberOfRenewalOptions" name="NumberOfRenewalOptions" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_NumberOfSecurities" name="NumberOfSecurities" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_OfferingPeriod" name="OfferingPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_OperatingLossCarryForwardsExpirationYear" name="OperatingLossCarryForwardsExpirationYear" type="xbrli:gYearItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_PaymentOfDeferredOfferingCosts" name="PaymentOfDeferredOfferingCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="pcvx_PaymentsOfCapitalLeaseObligations" name="PaymentsOfCapitalLeaseObligations" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="pcvx_PaymentsOfUnderwritingDiscountsAndCommissions" name="PaymentsOfUnderwritingDiscountsAndCommissions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="pcvx_PercentageOfFairValuePerShareOnTheGrantDate" name="PercentageOfFairValuePerShareOnTheGrantDate" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_PercentageOfPaymentsCompletionAgreedToDefer" name="PercentageOfPaymentsCompletionAgreedToDefer" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_PercentageOfProvisionsSubjectToStockholders" name="PercentageOfProvisionsSubjectToStockholders" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_PercentageOfRoyaltyPaymentOnAnnualNetSalesOfVaccineProductsForHumanHealth" name="PercentageOfRoyaltyPaymentOnAnnualNetSalesOfVaccineProductsForHumanHealth" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_PercentageOfRoyaltyPaymentOnNetSalesOfVaccineCompositionsForAnimalHealth" name="PercentageOfRoyaltyPaymentOnNetSalesOfVaccineCompositionsForAnimalHealth" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_PotentialFundingAmountOfAwardToDevelopVaccineToPreventInfections" name="PotentialFundingAmountOfAwardToDevelopVaccineToPreventInfections" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="pcvx_PotentialFundingCommittedByAward" name="PotentialFundingCommittedByAward" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="pcvx_PotentialFundingPeriodOfAwardToDevelopVaccineToPreventInfections" name="PotentialFundingPeriodOfAwardToDevelopVaccineToPreventInfections" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_PrefundedWarrantsPricePerShare" name="PrefundedWarrantsPricePerShare" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_ProceedsFromInitialPublicOfferingNetOfUnderwritersCommissionsAndDiscounts" name="ProceedsFromInitialPublicOfferingNetOfUnderwritersCommissionsAndDiscounts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="pcvx_ProceedsFromIssuanceFollowOnOffering" name="ProceedsFromIssuanceFollowOnOffering" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="pcvx_ProceedsFromIssuanceOfCommonStockNotYetReceived" name="ProceedsFromIssuanceOfCommonStockNotYetReceived" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="pcvx_ProceedsFromIssuanceOfCommonStockRelatedToEarlyExercisedStockOptions" name="ProceedsFromIssuanceOfCommonStockRelatedToEarlyExercisedStockOptions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="pcvx_PurchasePeriod" name="PurchasePeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_RemainingLiabilitiesRelatedToEarlyExercisedShares" name="RemainingLiabilitiesRelatedToEarlyExercisedShares" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="pcvx_ResearchAndDevelopmentExpenseToRelatedParty" name="ResearchAndDevelopmentExpenseToRelatedParty" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="pcvx_SaleOfCommonStockAuthorizedAmount" name="SaleOfCommonStockAuthorizedAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="pcvx_Section162MLimitation" name="Section162MLimitation" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantExercisedInPeriod" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantExercisedInPeriod" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantForfeitedInPeriod" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantForfeitedInPeriod" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantGrantedInPeriod" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantGrantedInPeriod" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesIncreaseInAvailableForGrant" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesIncreaseInAvailableForGrant" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_SharesIssuedPricePerShareUponFollowOnOffering" name="SharesIssuedPricePerShareUponFollowOnOffering" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_SharesIssuedUponFollowOnOfferingFullExerciseOfUnderwritersOptionToPurchaseAdditionalShares" name="SharesIssuedUponFollowOnOfferingFullExerciseOfUnderwritersOptionToPurchaseAdditionalShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_SharesIssuedUponFullExerciseOfUnderwritersOptionToPurchaseAdditionalShares" name="SharesIssuedUponFullExerciseOfUnderwritersOptionToPurchaseAdditionalShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_SharesPreFundedWarrantsToPurchase" name="SharesPreFundedWarrantsToPurchase" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_StockIssuedDuringPeriodSharesConversionOfCommonStockWarrant" name="StockIssuedDuringPeriodSharesConversionOfCommonStockWarrant" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_StockIssuedDuringPeriodSharesConversionOfPreferredStockWarrant" name="StockIssuedDuringPeriodSharesConversionOfPreferredStockWarrant" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_StockIssuedDuringPeriodSharesIssuanceOfCommonStockRelatedToEarlyExercisedStockOptions" name="StockIssuedDuringPeriodSharesIssuanceOfCommonStockRelatedToEarlyExercisedStockOptions" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_StockIssuedDuringPeriodSharesOfFollowOnOffering" name="StockIssuedDuringPeriodSharesOfFollowOnOffering" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_StockOptionsGrantedTerm" name="StockOptionsGrantedTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_TaxCreditCarryforwardExpirationYear" name="TaxCreditCarryforwardExpirationYear" type="xbrli:gYearItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_TemporaryEquityConversionOfPreferredStockShares" name="TemporaryEquityConversionOfPreferredStockShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_TemporaryEquityConversionOfPreferredStockValue" name="TemporaryEquityConversionOfPreferredStockValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="pcvx_TemporaryEquityStockIssuanceCosts" name="TemporaryEquityStockIssuanceCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="pcvx_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues" name="TemporaryEquityStockIssuedDuringPeriodSharesNewIssues" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_ThresholdLimitOnEquityPayments" name="ThresholdLimitOnEquityPayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="pcvx_UnrecognizedTaxBenefitsIncreasesDecreasesResultingFromPriorPeriodTaxPositions" name="UnrecognizedTaxBenefitsIncreasesDecreasesResultingFromPriorPeriodTaxPositions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="pcvx_FundingArrangementLineItems" name="FundingArrangementLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_IncomeTaxDisclosureLineItems" name="IncomeTaxDisclosureLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_ScheduleOfOrganizationConsolidationAndPresentationOfFinancialStatementsLineItems" name="ScheduleOfOrganizationConsolidationAndPresentationOfFinancialStatementsLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_AdditionalFacilityMember" name="AdditionalFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_ATMSalesAgreementMember" name="ATMSalesAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_CapitalLeasesLabEquipmentMember" name="CapitalLeasesLabEquipmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_CombatingAntibioticResistantBacteriaBiopharmaceuticalAcceleratorAgreementMember" name="CombatingAntibioticResistantBacteriaBiopharmaceuticalAcceleratorAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_CommonStockWarrantMember" name="CommonStockWarrantMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_ComputersAndComputerSoftwareMember" name="ComputersAndComputerSoftwareMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_CostReimbursementSubAwardAgreementMember" name="CostReimbursementSubAwardAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_HeadquartersFacilityMember" name="HeadquartersFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_JefferiesLimitedLiabilityCompanyMember" name="JefferiesLimitedLiabilityCompanyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_LabEquipmentMember" name="LabEquipmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_LicenseAgreementMember" name="LicenseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_LicenseAmendmentATwoMember" name="LicenseAmendmentATwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_LonzaLimitedMember" name="LonzaLimitedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_MarketOfferingMember" name="MarketOfferingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_NewCorporateHeadquartersFacilityMember" name="NewCorporateHeadquartersFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_PaloAltoMember" name="PaloAltoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_PneumococcalConjugateVaccineMember" name="PneumococcalConjugateVaccineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_PreferredStockWarrantMember" name="PreferredStockWarrantMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_RedeemableConvertiblePreferredStockWarrantMember" name="RedeemableConvertiblePreferredStockWarrantMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_SanCarlosMember" name="SanCarlosMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_SeriesARedeemableConvertiblePreferredStockMember" name="SeriesARedeemableConvertiblePreferredStockMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_SeriesBRedeemableConvertiblePreferredStockMember" name="SeriesBRedeemableConvertiblePreferredStockMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_SeriesCRedeemableConvertiblePreferredStockMember" name="SeriesCRedeemableConvertiblePreferredStockMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_SeriesDRedeemableConvertiblePreferredStockMember" name="SeriesDRedeemableConvertiblePreferredStockMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_SharesAvailableForFutureStockOptionGrantsMember" name="SharesAvailableForFutureStockOptionGrantsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_SupplyAgreementMember" name="SupplyAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_SutroBiopharmaIncMember" name="SutroBiopharmaIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_TwoThousandFourteenEquityIncentivePlanAndTwoThousandTwentyEquityIncentivePlanAndTwoThousandTwentyEmployeeStockPurchasePlanMember" name="TwoThousandFourteenEquityIncentivePlanAndTwoThousandTwentyEquityIncentivePlanAndTwoThousandTwentyEmployeeStockPurchasePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_TwoThousandFourteenEquityIncentivePlanMember" name="TwoThousandFourteenEquityIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_TwoThousandTwentyEmployeeStockPurchasePlanMember" name="TwoThousandTwentyEmployeeStockPurchasePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_TwoThousandTwentyEquityIncentivePlanAndTwoThousandFourteenEquityIncentivePlanMember" name="TwoThousandTwentyEquityIncentivePlanAndTwoThousandFourteenEquityIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_TwoThousandTwentyEquityIncentivePlanMember" name="TwoThousandTwentyEquityIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_FundingArrangementTable" name="FundingArrangementTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_IncomeTaxDisclosureTable" name="IncomeTaxDisclosureTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_ScheduleOfOrganizationConsolidationAndPresentationOfFinancialStatementsTable" name="ScheduleOfOrganizationConsolidationAndPresentationOfFinancialStatementsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="pcvx_AccruedResearchAndDevelopmentPolicyTextBlock" name="AccruedResearchAndDevelopmentPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_FundingArrangementTextBlock" name="FundingArrangementTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_RedeemableConvertiblePreferredStockTextBlock" name="RedeemableConvertiblePreferredStockTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_ScheduleOfCommonStockSharesReservedForFutureIssuanceTableTextBlock" name="ScheduleOfCommonStockSharesReservedForFutureIssuanceTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_ScheduleOfInformationRelatedToRightOfUseAssetsAndLeaseLiabilitiesTableTextBlock" name="ScheduleOfInformationRelatedToRightOfUseAssetsAndLeaseLiabilitiesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="pcvx_WarrantsDisclosureTextBlock" name="WarrantsDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
</xsd:schema>
